Climate and average weather in Suzhou
In Suzhou, the summers are oppressive, hot, showery, and partly cloudy and the winters are cold, snowy, and partly cloudy.
Over the course of the year, the temperature in Suzhou typically varies from 2°C to 32°C, and is rarely below -2°C or above 36°C. July is the hottest month of the year, while January is the coldest.
Based on the travel score, the best times of year to visit Suzhou for warm-weather activities are from mid April to early June and mid September to mid November.
- Hottest
- Jul
- 32°
- Coldest
- Jan
- 2°
- Wettest
- Jun
- 275 mm
- Driest
- Dec
- 55 mm
- Rain / yr
- 1421 mm
- 125 wet days
- Daylight
- 10.0–14.0 h
- shortest–longest
- Elevation
- 10 m
- 31.3°N
- Clearest
- Dec
- 49% cloud
Suzhou is prefecture-level city in Jiangsu, China, former capital of the kingdom of Wu.
- Air quality
- Very high
- PM2.5 47.5 µg/m³ · 2018
- Density
- 776/km²
- people per km²
- Founded
- ~514 BCE
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Suzhou weather by month, at a glance
The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.
Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around mid September to mid November.
Temperature through the year
Daily average highs and lows in Suzhou, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
The hot season lasts 3.7 months, from May 30 to September 20, with daily high temperatures above 26°C. The hottest month of the year in Suzhou is July, with an average high of 32°C and low of 27°C.
The cool season lasts 3.0 months, from December 3 to March 4, with daily high temperatures below 12°C. The coldest month of the year in Suzhou is January, with an average low of 2°C and high of 7°C.
Days typically run about 6°C warmer than nights year-round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 7 | 9 | 14 | 20 | 25 | 28 | 32 | 31 | 27 | 22 | 16 | 10 |
| Avg low (°C) | 2 | 4 | 8 | 13 | 18 | 22 | 27 | 26 | 22 | 17 | 11 | 5 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 7 | 2 |
| Feb | 9 | 4 |
| Mar | 14 | 8 |
| Apr | 20 | 13 |
| May | 25 | 18 |
| Jun | 28 | 22 |
| Jul | 32 | 27 |
| Aug | 31 | 26 |
| Sep | 27 | 22 |
| Oct | 22 | 17 |
| Nov | 16 | 11 |
| Dec | 10 | 5 |
How hot and cold Suzhou really feels
The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.
On the hottest afternoons, once humidity is folded in, Suzhou feels like about 41°C (around July 27). About 72 days a year carry some heat stress, and 27 of them tip into dangerous heat (feels-like above 39°C), peaking in July.
On the coldest nights, wind chill pulls the feels-like down to about -2°C (around January 17), with roughly 49 freezing days a year (feels-like at or below 0°C), worst in January.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°C) | 7 | 9 | 14 | 20 | 25 | 30 | 39 | 38 | 28 | 22 | 16 | 10 |
| Air high (°C) | 7 | 9 | 14 | 20 | 25 | 28 | 32 | 31 | 27 | 22 | 16 | 10 |
| Feels-like low (°C) | -1 | 0 | 5 | 13 | 18 | 22 | 26 | 26 | 22 | 17 | 10 | 2 |
| Air low (°C) | 2 | 4 | 8 | 13 | 18 | 22 | 27 | 26 | 22 | 17 | 11 | 5 |
| Feels-like high (°C) | Air high (°C) | Feels-like low (°C) | Air low (°C) | |
|---|---|---|---|---|
| Jan | 7 | 7 | -1 | 2 |
| Feb | 9 | 9 | 0 | 4 |
| Mar | 14 | 14 | 5 | 8 |
| Apr | 20 | 20 | 13 | 13 |
| May | 25 | 25 | 18 | 18 |
| Jun | 30 | 28 | 22 | 22 |
| Jul | 39 | 32 | 26 | 27 |
| Aug | 38 | 31 | 26 | 26 |
| Sep | 28 | 27 | 22 | 22 |
| Oct | 22 | 22 | 17 | 17 |
| Nov | 16 | 16 | 10 | 11 |
| Dec | 10 | 10 | 2 | 5 |
Average hourly temperature in Suzhou
A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on July afternoons, near 32°C, and coldest before dawn in January, near 2°C.
Suzhou weather by month
Every month at a glance. Click a month for its detailed page.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 7° / 2° | 78 | 9.1 | 1.1 | 10.2 | 1.0 |
| Feb | 9° / 4° | 81 | 9.4 | 0.8 | 10.9 | 1.9 |
| Mar | 14° / 8° | 117 | 12.5 | 0.2 | 11.8 | 3.7 |
| Apr | 20° / 13° | 119 | 10.8 | 0 | 12.7 | 5.9 |
| May | 25° / 18° | 142 | 10.8 | 0 | 13.6 | 6.6 |
| Jun | 28° / 22° | 275 | 14 | 0 | 14 | 5.3 |
| Jul | 32° / 27° | 171 | 13.1 | 0 | 13.8 | 3.7 |
| Aug | 31° / 26° | 160 | 14.3 | 0 | 13.1 | 3.9 |
| Sep | 27° / 22° | 95 | 9.6 | 0 | 12.2 | 6.3 |
| Oct | 22° / 17° | 62 | 6.6 | 0 | 11.2 | 7.3 |
| Nov | 16° / 11° | 67 | 8.3 | 0 | 10.4 | 5.3 |
| Dec | 10° / 5° | 55 | 6.9 | 0.4 | 10 | 2.3 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Suzhou gets about 1421 mm of precipitation a year. On a typical day the chance of rain is often wet, but that rises and falls sharply with the seasons.
The wetter season lasts 3.4 months, from around Jun 1 to Sep 12, peaking in June at about 57% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Oct 20.
June is the wettest month by volume, with 275 mm over about 14 wet days; December is the driest, with 55 mm. Some of the cold-season precipitation falls as snow.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 29 | 33 | 40 | 37 | 35 | 46 | 44 | 45 | 33 | 21 | 27 | 23 |
| Rain days | 9 | 9 | 13 | 11 | 11 | 14 | 13 | 14 | 10 | 7 | 8 | 7 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 29 | 9 |
| Feb | 33 | 9 |
| Mar | 40 | 13 |
| Apr | 37 | 11 |
| May | 35 | 11 |
| Jun | 46 | 14 |
| Jul | 44 | 13 |
| Aug | 45 | 14 |
| Sep | 33 | 10 |
| Oct | 21 | 7 |
| Nov | 27 | 8 |
| Dec | 23 | 7 |
Monthly rainfall
Over a full year, Suzhou collects about 1421 mm of rain across 125 wet days — roughly 118 mm in an average month.
It doesn’t fall evenly. June is the wettest month with 275 mm, while December is the driest at just 55 mm. The three wettest months alone bring about 43% of the year’s total, and some of the cold-season precipitation falls as snow.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 78 | 81 | 117 | 119 | 142 | 275 | 171 | 160 | 95 | 62 | 67 | 55 |
| Rain days | 9 | 9 | 13 | 11 | 11 | 14 | 13 | 14 | 10 | 7 | 8 | 7 |
| Snow days | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Rainfall (mm) | Rain days | Snow days | |
|---|---|---|---|
| Jan | 78 | 9 | 1 |
| Feb | 81 | 9 | 1 |
| Mar | 117 | 13 | 0 |
| Apr | 119 | 11 | 0 |
| May | 142 | 11 | 0 |
| Jun | 275 | 14 | 0 |
| Jul | 171 | 13 | 0 |
| Aug | 160 | 14 | 0 |
| Sep | 95 | 10 | 0 |
| Oct | 62 | 7 | 0 |
| Nov | 67 | 8 | 0 |
| Dec | 55 | 7 | 0 |
Snow in Suzhou
Average snowy days through the year, the snow-season span, and estimated snowfall — for ski trips and the perennial 'will there be snow at Christmas?' question.
Suzhou averages about 3 snowy days a year. Snow season runs roughly Dec 26 to Feb 23 — about 2 months.
January is snowiest, with roughly 1.1 day of snow and an estimated 5 cm of snowfall. Over the year that adds up to an estimated 12 cm of snow.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Snow days | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Snowfall (cm) | 5 | 5 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| Snow days | Snowfall (cm) | |
|---|---|---|
| Jan | 1 | 5 |
| Feb | 1 | 5 |
| Mar | 0 | 1 |
| Apr | 0 | 0 |
| May | 0 | 0 |
| Jun | 0 | 0 |
| Jul | 0 | 0 |
| Aug | 0 | 0 |
| Sep | 0 | 0 |
| Oct | 0 | 0 |
| Nov | 0 | 0 |
| Dec | 0 | 1 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Suzhou, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.
The clearer part of the year begins around July 24 and lasts for 6.7 months, ending around February 12. The clearest month is October, when the sky is clear, mostly clear, or partly cloudy 57% of the time on average.
The cloudier part of the year begins around February 13 and lasts for 5.3 months, ending around July 23. The cloudiest month is June, when it is overcast or mostly cloudy 75% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 47 | 42 | 35 | 37 | 37 | 25 | 33 | 46 | 50 | 57 | 55 | 56 |
| Cloudier (%) | 53 | 58 | 65 | 63 | 63 | 75 | 67 | 54 | 50 | 43 | 45 | 44 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 47 | 53 |
| Feb | 42 | 58 |
| Mar | 35 | 65 |
| Apr | 37 | 63 |
| May | 37 | 63 |
| Jun | 25 | 75 |
| Jul | 33 | 67 |
| Aug | 46 | 54 |
| Sep | 50 | 50 |
| Oct | 57 | 43 |
| Nov | 55 | 45 |
| Dec | 56 | 44 |
Daylight, sunrise and sunset
Hours of daylight through the year, with sunrise and sunset times.
The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 7, brings about 14 hours of light; the shortest, around January 1, only 10 hours — a swing of roughly 4 hours.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 10.2 | 10.9 | 11.8 | 12.7 | 13.6 | 14.0 | 13.8 | 13.1 | 12.2 | 11.2 | 10.4 | 10.0 |
| Sunrise (AM) | 7:02 | 6:46 | 6:14 | 5:35 | 5:06 | 4:57 | 5:08 | 5:27 | 5:46 | 6:06 | 6:31 | 6:55 |
| Sunset (PM) | 5:12 | 5:38 | 6:00 | 6:21 | 6:41 | 6:59 | 6:59 | 6:36 | 5:58 | 5:19 | 4:54 | 4:53 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 10.2 | 7:02 | 5:12 |
| Feb | 10.9 | 6:46 | 5:38 |
| Mar | 11.8 | 6:14 | 6:00 |
| Apr | 12.7 | 5:35 | 6:21 |
| May | 13.6 | 5:06 | 6:41 |
| Jun | 14.0 | 4:57 | 6:59 |
| Jul | 13.8 | 5:08 | 6:59 |
| Aug | 13.1 | 5:27 | 6:36 |
| Sep | 12.2 | 5:46 | 5:58 |
| Oct | 11.2 | 6:06 | 5:19 |
| Nov | 10.4 | 6:31 | 4:54 |
| Dec | 10.0 | 6:55 | 4:53 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Suzhou averages about 10 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 3 and 15 days.
The sunnier stretch runs 5.2 months, from around Sep 10 to Feb 15. The sunniest month is November, with roughly 14 sunny days (mixed).
The greyest month is June, down near 4 sunny days — about 68% fewer than the November peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 11 | 9 | 8 | 8 | 8 | 4 | 7 | 10 | 10 | 13 | 14 | 14 |
| Sky | Mixed | Mixed | Gloomy | Mixed | Gloomy | Gloomy | Gloomy | Mixed | Mixed | Mixed | Mixed | Mixed |
| Sunny days | Sky | |
|---|---|---|
| Jan | 11 | Mixed |
| Feb | 9 | Mixed |
| Mar | 8 | Gloomy |
| Apr | 8 | Mixed |
| May | 8 | Gloomy |
| Jun | 4 | Gloomy |
| Jul | 7 | Gloomy |
| Aug | 10 | Mixed |
| Sep | 10 | Mixed |
| Oct | 13 | Mixed |
| Nov | 14 | Mixed |
| Dec | 14 | Mixed |
Humidity comfort
Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.
Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.
In Suzhou, how humid it feels changes dramatically over the year.
The more humid part of the year lasts 5.3 months, from around May 5 to October 12. The muggiest month is June, when the air feels humid, muggy or worse about 97% of the time.
The most comfortable stretch runs from around October 13 to May 4, and February is the most comfortable month — the air is dry or comfortable 100% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 100 | 99 | 94 | 63 | 16 | 0 | 0 | 0 | 2 | 32 | 79 | 99 |
| Comfortable (%) | 0 | 1 | 5 | 20 | 24 | 3 | 0 | 0 | 8 | 29 | 13 | 1 |
| Humid (%) | 0 | 0 | 1 | 12 | 31 | 14 | 0 | 1 | 20 | 23 | 6 | 0 |
| Muggy (%) | 0 | 0 | 0 | 4 | 22 | 37 | 5 | 7 | 30 | 12 | 1 | 0 |
| Oppressive (%) | 0 | 0 | 0 | 1 | 7 | 27 | 19 | 22 | 25 | 3 | 0 | 0 |
| Miserable (%) | 0 | 0 | 0 | 0 | 1 | 19 | 76 | 69 | 15 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|---|---|---|
| Jan | 100 | 0 | 0 | 0 | 0 | 0 |
| Feb | 99 | 1 | 0 | 0 | 0 | 0 |
| Mar | 94 | 5 | 1 | 0 | 0 | 0 |
| Apr | 63 | 20 | 12 | 4 | 1 | 0 |
| May | 16 | 24 | 31 | 22 | 7 | 1 |
| Jun | 0 | 3 | 14 | 37 | 27 | 19 |
| Jul | 0 | 0 | 0 | 5 | 19 | 76 |
| Aug | 0 | 0 | 1 | 7 | 22 | 69 |
| Sep | 2 | 8 | 20 | 30 | 25 | 15 |
| Oct | 32 | 29 | 23 | 12 | 3 | 0 |
| Nov | 79 | 13 | 6 | 1 | 0 | 0 |
| Dec | 99 | 1 | 0 | 0 | 0 | 0 |
Wind
Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.
This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.
Wind in Suzhou is steady company: average speeds sit near 14 km/h — light breeze — in every month of the year, with no meaningful windy or calm season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 13 | 14 | 15 | 15 | 15 | 13 | 13 | 14 | 14 | 13 | 13 | 13 |
| Feels | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 13 | light breeze |
| Feb | 14 | light breeze |
| Mar | 15 | light breeze |
| Apr | 15 | light breeze |
| May | 15 | light breeze |
| Jun | 13 | light breeze |
| Jul | 13 | light breeze |
| Aug | 14 | light breeze |
| Sep | 14 | light breeze |
| Oct | 13 | light breeze |
| Nov | 13 | light breeze |
| Dec | 13 | light breeze |
Hazard calendar for Suzhou
When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.
Suzhou sits in the Pacific typhoon belt; the season peaks July–October.
Suzhou's rainy season runs May–August, when most of the year's rain falls.
Best time to visit Suzhou
To characterize how pleasant the weather is in Suzhou throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around early November, Suzhou is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.
Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.
The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best times of year to visit Suzhou for general outdoor tourist activities run from mid April to early June and again from mid September to mid November, with a peak score in the second week of October.
The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Travel score (0–10) | 1.0 | 1.9 | 3.7 | 5.9 | 6.6 | 5.3 | 3.7 | 4.0 | 6.3 | 7.3 | 5.3 | 2.3 |
| Rating | poor | poor | fair | good | good | fair | fair | fair | good | good | fair | poor |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 1.0 | poor |
| Feb | 1.9 | poor |
| Mar | 3.7 | fair |
| Apr | 5.9 | good |
| May | 6.6 | good |
| Jun | 5.3 | fair |
| Jul | 3.7 | fair |
| Aug | 4.0 | fair |
| Sep | 6.3 | good |
| Oct | 7.3 | good |
| Nov | 5.3 | fair |
| Dec | 2.3 | poor |
The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Suzhou for hot-weather activities is from early May to mid October, with a peak score in the second week of September.
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
What to pack for Suzhou, by month
Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.
For a warm-season trip around July (highs near 32°C), the essentials are light clothes, rain gear and sun protection. In the cold season around January (highs near 7°C), pack a warm layer, a heavy coat and rain gear.
In July, Suzhou sees daytime highs around 32°C and nights near 27°C. Pack light clothes. Worth having: rain gear and sun protection. About 13 days see rain.
UV index (midday) in Suzhou by month
Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.
Under clear skies, the midday UV index in Suzhou peaks around September 11 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 3 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 3 | 5 | 6 | 7 | 7 | 8 | 10 | 9 | 10 | 6 | 4 | 3 |
| Level | Moderate | Moderate | High | High | High | Very high | Very high | Very high | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 3 | Moderate |
| Feb | 5 | Moderate |
| Mar | 6 | High |
| Apr | 7 | High |
| May | 7 | High |
| Jun | 8 | Very high |
| Jul | 10 | Very high |
| Aug | 9 | Very high |
| Sep | 10 | Very high |
| Oct | 6 | High |
| Nov | 4 | Moderate |
| Dec | 3 | Moderate |
Average hourly UV index in Suzhou
Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.
The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
UV falls off far faster than brightness as the sun drops, so even in September the burn window is concentrated in the middle of the day: about 7.5 hours a day reach index 3 (protection recommended), and 5 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV ≥ 3 (h/day) | 2.5 | 4.5 | 5.5 | 6.5 | 7 | 8 | 8 | 8 | 7.5 | 5.5 | 3 | 1.5 |
| UV ≥ 6 (h/day) | 0 | 0 | 0 | 2.5 | 3.5 | 4.5 | 5.5 | 5 | 5 | 0 | 0 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 2.5 | 0 |
| Feb | 4.5 | 0 |
| Mar | 5.5 | 0 |
| Apr | 6.5 | 2.5 |
| May | 7 | 3.5 |
| Jun | 8 | 4.5 |
| Jul | 8 | 5.5 |
| Aug | 8 | 5 |
| Sep | 7.5 | 5 |
| Oct | 5.5 | 0 |
| Nov | 3 | 0 |
| Dec | 1.5 | 0 |
Air quality in Suzhou by month
Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.
Air quality in Suzhou is worst in December — around 67 µg/m³ PM2.5 (unhealthy), about 2.2× the cleanest month (August, 30 µg/m³).
Seasonal pattern from CAMS reanalysis, scaled to Suzhou's WHO annual average of 47.5 µg/m³.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 65 | 57 | 54 | 50 | 42 | 36 | 31 | 30 | 38 | 45 | 56 | 67 |
| Level | Unhealthy | Unhealthy | Poor | Poor | Poor | Poor | Moderate | Moderate | Poor | Poor | Unhealthy | Unhealthy |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 65 | Unhealthy |
| Feb | 57 | Unhealthy |
| Mar | 54 | Poor |
| Apr | 50 | Poor |
| May | 42 | Poor |
| Jun | 36 | Poor |
| Jul | 31 | Moderate |
| Aug | 30 | Moderate |
| Sep | 38 | Poor |
| Oct | 45 | Poor |
| Nov | 56 | Unhealthy |
| Dec | 67 | Unhealthy |
Growing season
Suzhou is mild enough that a frost-free day stays more likely than not even in midwinter. Nights are reliably above freezing from about February 16 to December 15 (303 days); outside that window a hard frost is an occasional risk.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 76 | 88 | 99 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 90 |
| Frost nights | 31 | 15 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 16 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 76 | 31 |
| Feb | 88 | 15 |
| Mar | 99 | 0 |
| Apr | 100 | 0 |
| May | 100 | 0 |
| Jun | 100 | 0 |
| Jul | 100 | 0 |
| Aug | 100 | 0 |
| Sep | 100 | 0 |
| Oct | 100 | 0 |
| Nov | 100 | 0 |
| Dec | 90 | 16 |
Growing degree days
Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Suzhou banks about 3,027 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around July.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 0 | 0 | 32 | 190 | 356 | 452 | 589 | 581 | 438 | 290 | 99 | 0 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 0 |
| Feb | 0 |
| Mar | 32 |
| Apr | 190 |
| May | 356 |
| Jun | 452 |
| Jul | 589 |
| Aug | 581 |
| Sep | 438 |
| Oct | 290 |
| Nov | 99 |
| Dec | 0 |
Solar energy
Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.
Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.
Suzhou receives about 4.0 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 2.5 and 5.6 kWh/m².
The brighter stretch of the year lasts 6.2 months, from around Mar 19 to Sep 24. The brightest month is July, averaging about 5.1 kWh/m² (bright).
The dimmest month is December, down near 2.5 kWh/m² — roughly 51% less than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 2.7 | 3.2 | 4.0 | 4.9 | 5.2 | 4.6 | 5.2 | 4.9 | 4.2 | 3.7 | 2.8 | 2.5 |
| Level | Moderate | Moderate | Moderate | Bright | Bright | Bright | Bright | Bright | Bright | Moderate | Moderate | Moderate |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 2.7 | Moderate |
| Feb | 3.2 | Moderate |
| Mar | 4.0 | Moderate |
| Apr | 4.9 | Bright |
| May | 5.2 | Bright |
| Jun | 4.6 | Bright |
| Jul | 5.2 | Bright |
| Aug | 4.9 | Bright |
| Sep | 4.2 | Bright |
| Oct | 3.7 | Moderate |
| Nov | 2.8 | Moderate |
| Dec | 2.5 | Moderate |
Where is Suzhou?
Suzhou sits at 31.3°N, 120.6°E, 10 m above sea level, in China. The nearest listed city is Wuxi, 41 km away.
What Suzhou looks like
Topography around Suzhou
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Suzhou.
Within 3 km, the terrain around Suzhou has only modest variations in elevation — a maximum elevation change of 21 m around an average of 7 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 329 m; within 80 km, significant variations in elevation — a maximum elevation change of 561 m.
The land around Suzhou is covered by artificial surfaces (84%) within 3 km, artificial surfaces (50%) and trees (20%) within 16 km, and cropland (33%), artificial surfaces (30%) and water (21%) within 80 km.
China travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type A / I
- 220 V · 50 Hz
- Prices
- ≈ 47% of US
- price level, 2025
- GDP per capita
- $13,862
- 2025
- Happiness
- 6.1 / 10
- World Happiness, 2025
- Homicide rate
- 0.5
- per 100k, 2020
- Road deaths
- 17.4
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Low
- EF EPI 464
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Suzhou (31.3041°, 120.5954°, elevation 10 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).