Climate and average weather in Jiufen
In Jiufen, the summers are oppressive, hot, showery, and partly cloudy and the winters are mild and mostly cloudy.
Over the course of the year, the temperature in Jiufen typically varies from 14°C to 30°C, and is rarely below 10°C or above 32°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 Jiufen for warm-weather activities are from late February to early June and mid September to early December.
- Hottest
- Jul
- 30°
- Coldest
- Jan
- 14°
- Wettest
- Oct
- 313 mm
- Driest
- Apr
- 128 mm
- Rain / yr
- 2399 mm
- 212 wet days
- Daylight
- 10.4–13.6 h
- shortest–longest
- Elevation
- 0 m
- 25.1°N
- Clearest
- Aug
- 65% cloud
Jiufen is mountain area in Ruifang District near Keelung, Taiwan.
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Jiufen 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 late February to early June.
Temperature through the year
Daily average highs and lows in Jiufen, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
The hot season lasts 4.0 months, from May 28 to September 27, with daily high temperatures above 27°C. The hottest month of the year in Jiufen is July, with an average high of 30°C and low of 27°C.
The cool season lasts 3.2 months, from December 9 to March 14, with daily high temperatures below 20°C. The coldest month of the year in Jiufen is January, with an average low of 14°C and high of 17°C.
Days typically run about 3°C warmer than nights year-round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 17 | 18 | 20 | 23 | 26 | 29 | 30 | 30 | 28 | 25 | 22 | 19 |
| Avg low (°C) | 14 | 15 | 16 | 19 | 22 | 25 | 27 | 27 | 25 | 22 | 20 | 16 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 17 | 14 |
| Feb | 18 | 15 |
| Mar | 20 | 16 |
| Apr | 23 | 19 |
| May | 26 | 22 |
| Jun | 29 | 25 |
| Jul | 30 | 27 |
| Aug | 30 | 27 |
| Sep | 28 | 25 |
| Oct | 25 | 22 |
| Nov | 22 | 20 |
| Dec | 19 | 16 |
How hot and cold Jiufen 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, Jiufen feels like about 37°C (around July 7). About 93 days a year carry some heat stress, peaking in July.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°C) | 17 | 18 | 20 | 23 | 26 | 33 | 37 | 36 | 31 | 25 | 22 | 19 |
| Air high (°C) | 17 | 18 | 20 | 23 | 26 | 29 | 30 | 30 | 28 | 25 | 22 | 19 |
| Feels-like low (°C) | 14 | 14 | 16 | 19 | 22 | 25 | 27 | 26 | 25 | 22 | 20 | 16 |
| Air low (°C) | 14 | 15 | 16 | 19 | 22 | 25 | 27 | 27 | 25 | 22 | 20 | 16 |
| Feels-like high (°C) | Air high (°C) | Feels-like low (°C) | Air low (°C) | |
|---|---|---|---|---|
| Jan | 17 | 17 | 14 | 14 |
| Feb | 18 | 18 | 14 | 15 |
| Mar | 20 | 20 | 16 | 16 |
| Apr | 23 | 23 | 19 | 19 |
| May | 26 | 26 | 22 | 22 |
| Jun | 33 | 29 | 25 | 25 |
| Jul | 37 | 30 | 27 | 27 |
| Aug | 36 | 30 | 26 | 27 |
| Sep | 31 | 28 | 25 | 25 |
| Oct | 25 | 25 | 22 | 22 |
| Nov | 22 | 22 | 20 | 20 |
| Dec | 19 | 19 | 16 | 16 |
Average hourly temperature in Jiufen
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 30°C, and coldest before dawn in January, near 14°C.
Jiufen weather by month
Every month at a glance. Click a month for its detailed page.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 17° / 14° | 174 | 20.1 | 10.6 | 4.1 |
| Feb | 18° / 15° | 160 | 17.7 | 11.1 | 4.4 |
| Mar | 20° / 16° | 137 | 17 | 11.8 | 5.1 |
| Apr | 23° / 19° | 128 | 15.5 | 12.6 | 5.7 |
| May | 26° / 22° | 185 | 17.6 | 13.2 | 5.4 |
| Jun | 29° / 25° | 163 | 16.3 | 13.5 | 4.5 |
| Jul | 30° / 27° | 154 | 14 | 13.4 | 4.4 |
| Aug | 30° / 27° | 223 | 17.6 | 12.9 | 4.2 |
| Sep | 28° / 25° | 257 | 17.8 | 12.2 | 4.9 |
| Oct | 25° / 22° | 313 | 19.3 | 11.4 | 5.3 |
| Nov | 22° / 20° | 278 | 19.2 | 10.8 | 5.1 |
| Dec | 19° / 16° | 227 | 19.5 | 10.5 | 4.6 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Jiufen gets about 2399 mm of precipitation a year. On a typical day the chance of rain is very wet, but that rises and falls sharply with the seasons.
The wetter season lasts 6.3 months, from around Aug 27 to Mar 6, peaking in January at about 68% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jul 19.
October is the wettest month by volume, with 313 mm over about 19 wet days; April is the driest, with 128 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 65 | 63 | 56 | 52 | 56 | 54 | 46 | 56 | 59 | 63 | 64 | 63 |
| Rain days | 20 | 18 | 17 | 16 | 18 | 16 | 14 | 18 | 18 | 19 | 19 | 20 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 65 | 20 |
| Feb | 63 | 18 |
| Mar | 56 | 17 |
| Apr | 52 | 16 |
| May | 56 | 18 |
| Jun | 54 | 16 |
| Jul | 46 | 14 |
| Aug | 56 | 18 |
| Sep | 59 | 18 |
| Oct | 63 | 19 |
| Nov | 64 | 19 |
| Dec | 63 | 20 |
Monthly rainfall
Over a full year, Jiufen collects about 2399 mm of rain across 212 wet days — roughly 200 mm in an average month.
It doesn’t fall evenly. October is the wettest month with 313 mm, while April is the driest at just 128 mm. The three wettest months alone bring about 35% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 174 | 160 | 137 | 128 | 185 | 163 | 154 | 223 | 257 | 313 | 278 | 227 |
| Rain days | 20 | 18 | 17 | 16 | 18 | 16 | 14 | 18 | 18 | 19 | 19 | 20 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 174 | 20 |
| Feb | 160 | 18 |
| Mar | 137 | 17 |
| Apr | 128 | 16 |
| May | 185 | 18 |
| Jun | 163 | 16 |
| Jul | 154 | 14 |
| Aug | 223 | 18 |
| Sep | 257 | 18 |
| Oct | 313 | 19 |
| Nov | 278 | 19 |
| Dec | 227 | 20 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Jiufen, 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 3 and lasts for 4.4 months, ending around November 14. The clearest month is August, when the sky is clear, mostly clear, or partly cloudy 43% of the time on average.
The cloudier part of the year begins around April 19 and lasts for 2.5 months, ending around July 2. The cloudiest month is June, when it is overcast or mostly cloudy 82% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 23 | 24 | 31 | 31 | 24 | 18 | 39 | 43 | 43 | 34 | 28 | 24 |
| Cloudier (%) | 77 | 76 | 69 | 69 | 76 | 82 | 61 | 57 | 57 | 66 | 72 | 76 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 23 | 77 |
| Feb | 24 | 76 |
| Mar | 31 | 69 |
| Apr | 31 | 69 |
| May | 24 | 76 |
| Jun | 18 | 82 |
| Jul | 39 | 61 |
| Aug | 43 | 57 |
| Sep | 43 | 57 |
| Oct | 34 | 66 |
| Nov | 28 | 72 |
| Dec | 24 | 76 |
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 16, brings about 13 h 36 min of light; the shortest, around December 15, only 10 h 24 min — a swing of roughly 3 h 12 min.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 10.6 | 11.1 | 11.8 | 12.6 | 13.2 | 13.5 | 13.4 | 12.9 | 12.2 | 11.4 | 10.8 | 10.5 |
| Sunrise (AM) | 6:44 | 6:33 | 6:08 | 5:35 | 5:12 | 5:06 | 5:16 | 5:30 | 5:43 | 5:56 | 6:15 | 6:35 |
| Sunset (PM) | 5:20 | 5:41 | 5:57 | 6:10 | 6:25 | 6:39 | 6:41 | 6:23 | 5:51 | 5:20 | 5:01 | 5:02 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 10.6 | 6:44 | 5:20 |
| Feb | 11.1 | 6:33 | 5:41 |
| Mar | 11.8 | 6:08 | 5:57 |
| Apr | 12.6 | 5:35 | 6:10 |
| May | 13.2 | 5:12 | 6:25 |
| Jun | 13.5 | 5:06 | 6:39 |
| Jul | 13.4 | 5:16 | 6:41 |
| Aug | 12.9 | 5:30 | 6:23 |
| Sep | 12.2 | 5:43 | 5:51 |
| Oct | 11.4 | 5:56 | 5:20 |
| Nov | 10.8 | 6:15 | 5:01 |
| Dec | 10.5 | 6:35 | 5:02 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Jiufen averages about 5 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 2 and 9 days.
The sunnier stretch runs 3.4 months, from around Jun 30 to Oct 9. The sunniest month is July, with roughly 8 sunny days (gloomy).
The greyest month is June, down near 3 sunny days — about 64% fewer than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 4 | 4 | 5 | 5 | 4 | 3 | 8 | 8 | 7 | 5 | 5 | 4 |
| Sky | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Mixed | Gloomy | Gloomy | Gloomy | Gloomy |
| Sunny days | Sky | |
|---|---|---|
| Jan | 4 | Gloomy |
| Feb | 4 | Gloomy |
| Mar | 5 | Gloomy |
| Apr | 5 | Gloomy |
| May | 4 | Gloomy |
| Jun | 3 | Gloomy |
| Jul | 8 | Gloomy |
| Aug | 8 | Mixed |
| Sep | 7 | Gloomy |
| Oct | 5 | Gloomy |
| Nov | 5 | Gloomy |
| Dec | 4 | Gloomy |
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 Jiufen, how humid it feels changes dramatically over the year.
The more humid part of the year lasts 7.2 months, from around April 12 to November 16. The muggiest month is June, when the air feels humid, muggy or worse about 100% of the time.
The most comfortable stretch runs from around November 17 to April 11, and January is the most comfortable month — the air is dry or comfortable 80% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 52 | 44 | 29 | 9 | 1 | 0 | 0 | 0 | 0 | 1 | 10 | 36 |
| Comfortable (%) | 28 | 30 | 25 | 16 | 4 | 0 | 0 | 0 | 0 | 9 | 19 | 27 |
| Humid (%) | 18 | 22 | 32 | 25 | 11 | 1 | 0 | 0 | 5 | 21 | 28 | 26 |
| Muggy (%) | 2 | 3 | 13 | 31 | 25 | 7 | 0 | 1 | 15 | 30 | 29 | 10 |
| Oppressive (%) | 0 | 0 | 1 | 19 | 48 | 30 | 10 | 17 | 43 | 35 | 13 | 1 |
| Miserable (%) | 0 | 0 | 0 | 0 | 11 | 61 | 90 | 82 | 37 | 5 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|---|---|---|
| Jan | 52 | 28 | 18 | 2 | 0 | 0 |
| Feb | 44 | 30 | 22 | 3 | 0 | 0 |
| Mar | 29 | 25 | 32 | 13 | 1 | 0 |
| Apr | 9 | 16 | 25 | 31 | 19 | 0 |
| May | 1 | 4 | 11 | 25 | 48 | 11 |
| Jun | 0 | 0 | 1 | 7 | 30 | 61 |
| Jul | 0 | 0 | 0 | 0 | 10 | 90 |
| Aug | 0 | 0 | 0 | 1 | 17 | 82 |
| Sep | 0 | 0 | 5 | 15 | 43 | 37 |
| Oct | 1 | 9 | 21 | 30 | 35 | 5 |
| Nov | 10 | 19 | 28 | 29 | 13 | 0 |
| Dec | 36 | 27 | 26 | 10 | 1 | 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.
Across the year, average wind speed in Jiufen is typically light breeze, near 12 km/h, and varies moderately with the seasons.
The windier part of the year lasts 6.1 months, from around Sep 12 to Mar 17. The windiest month is December, averaging about 16 km/h (light breeze).
The calmer part of the year runs from around Mar 18 to Sep 11, with June the calmest month at about 7 km/h.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 15 | 14 | 12 | 10 | 9 | 7 | 8 | 10 | 13 | 15 | 15 | 16 |
| Feels | light breeze | light breeze | light breeze | calm | calm | calm | calm | calm | light breeze | light breeze | light breeze | light breeze |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 15 | light breeze |
| Feb | 14 | light breeze |
| Mar | 12 | light breeze |
| Apr | 10 | calm |
| May | 9 | calm |
| Jun | 7 | calm |
| Jul | 8 | calm |
| Aug | 10 | calm |
| Sep | 13 | light breeze |
| Oct | 15 | light breeze |
| Nov | 15 | light breeze |
| Dec | 16 | light breeze |
Hazard calendar for Jiufen
When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.
Jiufen sits in the Pacific typhoon belt; the season peaks July–October.
Best time to visit Jiufen
To characterize how pleasant the weather is in Jiufen throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around late May, Jiufen 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 Jiufen for general outdoor tourist activities run from late February to early June and again from mid September to early December, with a peak score in the last week of April.
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) | 4.1 | 4.4 | 5.1 | 5.7 | 5.3 | 4.5 | 4.4 | 4.2 | 4.9 | 5.3 | 5.1 | 4.6 |
| Rating | fair | fair | fair | good | fair | fair | fair | fair | fair | fair | fair | fair |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 4.1 | fair |
| Feb | 4.4 | fair |
| Mar | 5.1 | fair |
| Apr | 5.7 | good |
| May | 5.3 | fair |
| Jun | 4.5 | fair |
| Jul | 4.4 | fair |
| Aug | 4.2 | fair |
| Sep | 4.9 | fair |
| Oct | 5.3 | fair |
| Nov | 5.1 | fair |
| Dec | 4.6 | fair |
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 Jiufen for hot-weather activities is from late April to early October, with a peak score in the last week of July.
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 Jiufen, 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 30°C), the essentials are light clothes, rain gear and sun protection. In the cold season around January (highs near 17°C), pack rain gear.
In July, Jiufen sees daytime highs around 30°C and nights near 27°C. Pack light clothes and rain gear. Worth having: sun protection. About 14 days see rain.
Sea temperature near Jiufen
Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.
The sea offshore is warmest in August at about 28°C and coldest in January near 21°C.
The water stays above 20°C all year — warm enough for a swim any month.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 21 | 21 | 22 | 24 | 25 | 27 | 28 | 28 | 27 | 26 | 24 | 23 |
| Comfort | Refreshing | Refreshing | Refreshing | Refreshing | Warm | Warm | Tropical | Tropical | Warm | Warm | Warm | Refreshing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 21 | Refreshing |
| Feb | 21 | Refreshing |
| Mar | 22 | Refreshing |
| Apr | 24 | Refreshing |
| May | 25 | Warm |
| Jun | 27 | Warm |
| Jul | 28 | Tropical |
| Aug | 28 | Tropical |
| Sep | 27 | Warm |
| Oct | 26 | Warm |
| Nov | 24 | Warm |
| Dec | 23 | Refreshing |
UV index (midday) in Jiufen 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 Jiufen peaks around July 13 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 4 (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) | 5 | 7 | 9 | 8 | 10 | 11 | 12 | 11 | 11 | 8 | 7 | 4 |
| Level | Moderate | Very high | Very high | Very high | Extreme | Extreme | Extreme | Extreme | Extreme | Very high | High | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 5 | Moderate |
| Feb | 7 | Very high |
| Mar | 9 | Very high |
| Apr | 8 | Very high |
| May | 10 | Extreme |
| Jun | 11 | Extreme |
| Jul | 12 | Extreme |
| Aug | 11 | Extreme |
| Sep | 11 | Extreme |
| Oct | 8 | Very high |
| Nov | 7 | High |
| Dec | 4 | Moderate |
Average hourly UV index in Jiufen
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 July the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 6.5 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) | 4.5 | 6 | 7 | 7 | 8 | 8.5 | 8.5 | 8 | 7.5 | 6.5 | 5.5 | 4 |
| UV ≥ 6 (h/day) | 0 | 3 | 4.5 | 4 | 5.5 | 6 | 6.5 | 5.5 | 5.5 | 3.5 | 2 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 4.5 | 0 |
| Feb | 6 | 3 |
| Mar | 7 | 4.5 |
| Apr | 7 | 4 |
| May | 8 | 5.5 |
| Jun | 8.5 | 6 |
| Jul | 8.5 | 6.5 |
| Aug | 8 | 5.5 |
| Sep | 7.5 | 5.5 |
| Oct | 6.5 | 3.5 |
| Nov | 5.5 | 2 |
| Dec | 4 | 0 |
Air quality in Jiufen 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 Jiufen is worst in April — around 52 µg/m³ PM2.5 (poor), about 2.1× the cleanest month (October, 25 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 38 | 43 | 51 | 52 | 44 | 41 | 32 | 32 | 30 | 25 | 32 | 32 |
| Level | Poor | Poor | Poor | Poor | Poor | Poor | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 38 | Poor |
| Feb | 43 | Poor |
| Mar | 51 | Poor |
| Apr | 52 | Poor |
| May | 44 | Poor |
| Jun | 41 | Poor |
| Jul | 32 | Moderate |
| Aug | 32 | Moderate |
| Sep | 30 | Moderate |
| Oct | 25 | Moderate |
| Nov | 32 | Moderate |
| Dec | 32 | Moderate |
Growing season
Jiufen is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Frost nights | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 100 | 0 |
| Feb | 100 | 0 |
| Mar | 100 | 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 | 100 | 0 |
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. Jiufen banks about 4,480 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) | 180 | 172 | 245 | 330 | 439 | 508 | 570 | 562 | 492 | 423 | 326 | 233 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 180 |
| Feb | 172 |
| Mar | 245 |
| Apr | 330 |
| May | 439 |
| Jun | 508 |
| Jul | 570 |
| Aug | 562 |
| Sep | 492 |
| Oct | 423 |
| Nov | 326 |
| Dec | 233 |
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.
Jiufen receives about 3.9 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 2.0 and 5.9 kWh/m².
The brighter stretch of the year lasts 6.3 months, from around Mar 25 to Oct 2. The brightest month is July, averaging about 5.9 kWh/m² (bright).
The dimmest month is December, down near 2.1 kWh/m² — roughly 65% less than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 2.2 | 2.7 | 3.7 | 4.5 | 4.8 | 5.2 | 5.9 | 5.4 | 4.6 | 3.5 | 2.5 | 2.0 |
| Level | Moderate | Moderate | Moderate | Bright | Bright | Bright | Bright | Bright | Bright | Moderate | Moderate | Moderate |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 2.2 | Moderate |
| Feb | 2.7 | Moderate |
| Mar | 3.7 | Moderate |
| Apr | 4.5 | Bright |
| May | 4.8 | Bright |
| Jun | 5.2 | Bright |
| Jul | 5.9 | Bright |
| Aug | 5.4 | Bright |
| Sep | 4.6 | Bright |
| Oct | 3.5 | Moderate |
| Nov | 2.5 | Moderate |
| Dec | 2.0 | Moderate |
Where is Jiufen?
Jiufen sits at 25.1°N, 121.8°E, 0 m above sea level, in Taiwan. The nearest listed city is Keelung, 11 km away.
Topography around Jiufen
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Jiufen.
Within 3 km, the terrain around Jiufen has large variations in elevation — a maximum elevation change of 710 m around an average of 221 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 752 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,425 m.
The land around Jiufen is covered by trees (77%) within 3 km, trees (48%) and water (48%) within 16 km, and water (64%) and trees (29%) within 80 km.
Taiwan travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B
- 110 / 220 V · 60 Hz
- Happiness
- 6.7 / 10
- World Happiness, 2025
- 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 Jiufen (25.1096°, 121.8442°, elevation 0 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). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).