Climate and average weather in Sylhet
In Sylhet, the summers are oppressive, hot, wet, and mostly cloudy and the winters are warm and clear.
Over the course of the year, the temperature in Sylhet typically varies from 11°C to 31°C, and is rarely below 8°C or above 34°C. August is the hottest month of the year, while January is the coldest.
Based on the travel score, the best time of year to visit Sylhet for warm-weather activities is from mid November to early March.
- Hottest
- Aug
- 31°
- Coldest
- Jan
- 11°
- Wettest
- Jun
- 953 mm
- Driest
- Jan
- 10 mm
- Rain / yr
- 4971 mm
- 203 wet days
- Daylight
- 10.5–13.5 h
- shortest–longest
- Elevation
- 26 m
- 24.9°N
- Clearest
- Dec
- 20% cloud
Sylhet is capital and largest city of Sylhet Division, Bangladesh.
- Air quality
- Severe
- PM2.5 59.8 µg/m³ · 2018
- Density
- 8,943/km²
- people per km²
- Founded
- 1867
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Sylhet 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 November to early March.
Temperature through the year
Daily average highs and lows in Sylhet, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
Temperatures in Sylhet stay fairly even through the year, without a distinct hot or cool season. The warmest month is August, with an average high of 31°C and low of 26°C; the coolest is January, with an average low of 11°C and high of 24°C.
Days typically run about 9°C warmer than nights, with the widest day–night swing (around 12°C) in February.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 24 | 26 | 29 | 29 | 30 | 30 | 31 | 31 | 31 | 30 | 28 | 25 |
| Avg low (°C) | 11 | 14 | 18 | 21 | 23 | 25 | 25 | 26 | 25 | 23 | 17 | 13 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 24 | 11 |
| Feb | 26 | 14 |
| Mar | 29 | 18 |
| Apr | 29 | 21 |
| May | 30 | 23 |
| Jun | 30 | 25 |
| Jul | 31 | 25 |
| Aug | 31 | 26 |
| Sep | 31 | 25 |
| Oct | 30 | 23 |
| Nov | 28 | 17 |
| Dec | 25 | 13 |
How hot and cold Sylhet 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, Sylhet feels like about 39°C (around August 10). About 196 days a year carry some heat stress, and 13 of them tip into dangerous heat (feels-like above 39°C), peaking in August.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°C) | 23 | 26 | 29 | 32 | 35 | 37 | 38 | 39 | 38 | 34 | 29 | 25 |
| Air high (°C) | 24 | 26 | 29 | 29 | 30 | 30 | 31 | 31 | 31 | 30 | 28 | 25 |
| Feels-like low (°C) | 11 | 14 | 17 | 21 | 23 | 25 | 25 | 26 | 25 | 22 | 17 | 13 |
| Air low (°C) | 11 | 14 | 18 | 21 | 23 | 25 | 25 | 26 | 25 | 23 | 17 | 13 |
| Feels-like high (°C) | Air high (°C) | Feels-like low (°C) | Air low (°C) | |
|---|---|---|---|---|
| Jan | 23 | 24 | 11 | 11 |
| Feb | 26 | 26 | 14 | 14 |
| Mar | 29 | 29 | 17 | 18 |
| Apr | 32 | 29 | 21 | 21 |
| May | 35 | 30 | 23 | 23 |
| Jun | 37 | 30 | 25 | 25 |
| Jul | 38 | 31 | 25 | 25 |
| Aug | 39 | 31 | 26 | 26 |
| Sep | 38 | 31 | 25 | 25 |
| Oct | 34 | 30 | 22 | 23 |
| Nov | 29 | 28 | 17 | 17 |
| Dec | 25 | 25 | 13 | 13 |
Average hourly temperature in Sylhet
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 August afternoons, near 31°C, and coldest before dawn in January, near 11°C.
Sylhet 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 | 24° / 11° | 10 | 1.8 | 10.6 | 9.0 |
| Feb | 26° / 14° | 48 | 4.6 | 11.1 | 8.2 |
| Mar | 29° / 18° | 187 | 11.2 | 11.8 | 6.1 |
| Apr | 29° / 21° | 560 | 21.4 | 12.6 | 4.0 |
| May | 30° / 23° | 759 | 27.6 | 13.2 | 3.1 |
| Jun | 30° / 25° | 953 | 29.5 | 13.5 | 2.5 |
| Jul | 31° / 25° | 941 | 30.8 | 13.4 | 2.3 |
| Aug | 31° / 26° | 733 | 30.7 | 12.9 | 2.3 |
| Sep | 31° / 25° | 523 | 27.6 | 12.2 | 2.6 |
| Oct | 30° / 23° | 217 | 14.8 | 11.4 | 4.7 |
| Nov | 28° / 17° | 28 | 2.3 | 10.8 | 7.8 |
| Dec | 25° / 13° | 12 | 1.1 | 10.5 | 9.1 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Sylhet gets about 4971 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 6.5 months, from around Mar 28 to Oct 12, peaking in June at about 100% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Nov 29.
June is the wettest month by volume, with 953 mm over about 30 wet days; January is the driest, with 10 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 6 | 16 | 37 | 71 | 89 | 98 | 99 | 99 | 91 | 48 | 8 | 4 |
| Rain days | 2 | 5 | 11 | 21 | 28 | 30 | 31 | 31 | 28 | 15 | 2 | 1 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 6 | 2 |
| Feb | 16 | 5 |
| Mar | 37 | 11 |
| Apr | 71 | 21 |
| May | 89 | 28 |
| Jun | 98 | 30 |
| Jul | 99 | 31 |
| Aug | 99 | 31 |
| Sep | 91 | 28 |
| Oct | 48 | 15 |
| Nov | 8 | 2 |
| Dec | 4 | 1 |
Monthly rainfall
Over a full year, Sylhet collects about 4971 mm of rain across 203 wet days — roughly 414 mm in an average month.
It doesn’t fall evenly. June is the wettest month with 953 mm, while January is the driest at just 10 mm. The three wettest months alone bring about 53% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 10 | 48 | 187 | 560 | 759 | 953 | 941 | 733 | 523 | 217 | 28 | 12 |
| Rain days | 2 | 5 | 11 | 21 | 28 | 30 | 31 | 31 | 28 | 15 | 2 | 1 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 10 | 2 |
| Feb | 48 | 5 |
| Mar | 187 | 11 |
| Apr | 560 | 21 |
| May | 759 | 28 |
| Jun | 953 | 30 |
| Jul | 941 | 31 |
| Aug | 733 | 31 |
| Sep | 523 | 28 |
| Oct | 217 | 15 |
| Nov | 28 | 2 |
| Dec | 12 | 1 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Sylhet, 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 October 7 and lasts for 6.5 months, ending around April 21. The clearest month is December, when the sky is clear, mostly clear, or partly cloudy 90% of the time on average.
The cloudier part of the year begins around April 22 and lasts for 5.5 months, ending around October 6. The cloudiest month is July, when it is overcast or mostly cloudy 97% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 89 | 87 | 79 | 58 | 45 | 13 | 3 | 5 | 22 | 67 | 86 | 90 |
| Cloudier (%) | 11 | 13 | 21 | 42 | 55 | 87 | 97 | 95 | 78 | 33 | 14 | 10 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 89 | 11 |
| Feb | 87 | 13 |
| Mar | 79 | 21 |
| Apr | 58 | 42 |
| May | 45 | 55 |
| Jun | 13 | 87 |
| Jul | 3 | 97 |
| Aug | 5 | 95 |
| Sep | 22 | 78 |
| Oct | 67 | 33 |
| Nov | 86 | 14 |
| Dec | 90 | 10 |
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 3, brings about 13 h 30 min of light; the shortest, around January 1, only 10 h 30 min — a swing of roughly 3 hours.
| 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 | 5:13 | 5:07 | 5:16 | 5:30 | 5:43 | 5:55 | 6:15 | 6:35 |
| Sunset (PM) | 5:20 | 5:41 | 5:57 | 6:10 | 6:25 | 6:39 | 6:40 | 6:23 | 5:51 | 5:20 | 5:01 | 5:03 |
| 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 | 5:13 | 6:25 |
| Jun | 13.5 | 5:07 | 6:39 |
| Jul | 13.4 | 5:16 | 6:40 |
| Aug | 12.9 | 5:30 | 6:23 |
| Sep | 12.2 | 5:43 | 5:51 |
| Oct | 11.4 | 5:55 | 5:20 |
| Nov | 10.8 | 6:15 | 5:01 |
| Dec | 10.5 | 6:35 | 5:03 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Sylhet averages about 13 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 0 and 25 days.
The sunnier stretch runs 5.9 months, from around Oct 9 to Apr 7. The sunniest month is November, with roughly 24 sunny days (brilliant).
The greyest month is July, down near 0 sunny days — about 99% fewer than the November peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 25 | 22 | 20 | 11 | 7 | 2 | 0 | 1 | 4 | 17 | 24 | 26 |
| Sky | Brilliant | Brilliant | Bright | Mixed | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Bright | Brilliant | Brilliant |
| Sunny days | Sky | |
|---|---|---|
| Jan | 25 | Brilliant |
| Feb | 22 | Brilliant |
| Mar | 20 | Bright |
| Apr | 11 | Mixed |
| May | 7 | Gloomy |
| Jun | 2 | Gloomy |
| Jul | 0 | Gloomy |
| Aug | 1 | Gloomy |
| Sep | 4 | Gloomy |
| Oct | 17 | Bright |
| Nov | 24 | Brilliant |
| Dec | 26 | Brilliant |
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 Sylhet, how humid it feels changes dramatically over the year.
The more humid part of the year lasts 8.2 months, from around March 16 to November 19. The muggiest month is April, when the air feels humid, muggy or worse about 99% of the time.
The most comfortable stretch runs from around November 20 to March 15, and January is the most comfortable month — the air is dry or comfortable 97% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 59 | 31 | 6 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 30 |
| Comfortable (%) | 38 | 45 | 20 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 18 | 51 |
| Humid (%) | 2 | 18 | 35 | 5 | 0 | 0 | 0 | 0 | 0 | 3 | 40 | 17 |
| Muggy (%) | 0 | 5 | 33 | 40 | 7 | 0 | 0 | 0 | 0 | 20 | 31 | 1 |
| Oppressive (%) | 0 | 0 | 7 | 49 | 57 | 12 | 2 | 0 | 10 | 46 | 9 | 0 |
| Miserable (%) | 0 | 0 | 0 | 5 | 36 | 88 | 98 | 100 | 90 | 31 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|---|---|---|
| Jan | 59 | 38 | 2 | 0 | 0 | 0 |
| Feb | 31 | 45 | 18 | 5 | 0 | 0 |
| Mar | 6 | 20 | 35 | 33 | 7 | 0 |
| Apr | 0 | 1 | 5 | 40 | 49 | 5 |
| May | 0 | 0 | 0 | 7 | 57 | 36 |
| Jun | 0 | 0 | 0 | 0 | 12 | 88 |
| Jul | 0 | 0 | 0 | 0 | 2 | 98 |
| Aug | 0 | 0 | 0 | 0 | 0 | 100 |
| Sep | 0 | 0 | 0 | 0 | 10 | 90 |
| Oct | 0 | 0 | 3 | 20 | 46 | 31 |
| Nov | 2 | 18 | 40 | 31 | 9 | 0 |
| Dec | 30 | 51 | 17 | 1 | 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 Sylhet is steady company: average speeds sit near 4 km/h — calm — 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) | 3 | 4 | 4 | 5 | 4 | 5 | 5 | 4 | 4 | 4 | 3 | 3 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 3 | calm |
| Feb | 4 | calm |
| Mar | 4 | calm |
| Apr | 5 | calm |
| May | 4 | calm |
| Jun | 5 | calm |
| Jul | 5 | calm |
| Aug | 4 | calm |
| Sep | 4 | calm |
| Oct | 4 | calm |
| Nov | 3 | calm |
| Dec | 3 | calm |
Hazard calendar for Sylhet
When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.
Sylhet's monsoon runs April–September, when most of the year's rain falls.
Best time to visit Sylhet
To characterize how pleasant the weather is in Sylhet throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around late February, Sylhet 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 time of year to visit Sylhet for general outdoor tourist activities is from mid November to early March, with a peak score in the last week of December.
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) | 9.0 | 8.2 | 6.1 | 4.0 | 3.1 | 2.5 | 2.3 | 2.3 | 2.7 | 4.7 | 7.8 | 9.1 |
| Rating | ideal | ideal | good | fair | poor | poor | poor | poor | poor | fair | ideal | ideal |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 9.0 | ideal |
| Feb | 8.2 | ideal |
| Mar | 6.1 | good |
| Apr | 4.0 | fair |
| May | 3.1 | poor |
| Jun | 2.5 | poor |
| Jul | 2.3 | poor |
| Aug | 2.3 | poor |
| Sep | 2.7 | poor |
| Oct | 4.7 | fair |
| Nov | 7.8 | ideal |
| Dec | 9.1 | ideal |
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 Sylhet for hot-weather activities is from late October to late March, with a peak score in the third week of November.
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 Sylhet, 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 August (highs near 31°C), the essentials are light clothes and rain gear. In the cold season around January (highs near 24°C), pack light clothes.
In August, Sylhet sees daytime highs around 31°C and nights near 26°C. Pack light clothes and rain gear. About 31 days see rain.
UV index (midday) in Sylhet 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 Sylhet peaks around July 21 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 17 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) | 4 | 5 | 8 | 7 | 8 | 6 | 12 | 10 | 11 | 6 | 6 | 5 |
| Level | Moderate | Moderate | Very high | High | Very high | High | Extreme | Extreme | Extreme | High | High | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 4 | Moderate |
| Feb | 5 | Moderate |
| Mar | 8 | Very high |
| Apr | 7 | High |
| May | 8 | Very high |
| Jun | 6 | High |
| Jul | 12 | Extreme |
| Aug | 10 | Extreme |
| Sep | 11 | Extreme |
| Oct | 6 | High |
| Nov | 6 | High |
| Dec | 5 | Moderate |
Average hourly UV index in Sylhet
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 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 | 4.5 | 6.5 | 6.5 | 7.5 | 6.5 | 8.5 | 8 | 7.5 | 5.5 | 5 | 4.5 |
| UV ≥ 6 (h/day) | 0 | 0 | 3.5 | 2.5 | 4.5 | 2 | 6 | 5.5 | 5.5 | 1 | 0 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 4 | 0 |
| Feb | 4.5 | 0 |
| Mar | 6.5 | 3.5 |
| Apr | 6.5 | 2.5 |
| May | 7.5 | 4.5 |
| Jun | 6.5 | 2 |
| Jul | 8.5 | 6 |
| Aug | 8 | 5.5 |
| Sep | 7.5 | 5.5 |
| Oct | 5.5 | 1 |
| Nov | 5 | 0 |
| Dec | 4.5 | 0 |
Air quality in Sylhet 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 Sylhet is worst in January — around 100 µg/m³ PM2.5 (unhealthy), about 4.3× the cleanest month (July, 23 µg/m³).
Seasonal pattern from CAMS reanalysis, scaled to Sylhet's WHO annual average of 59.8 µg/m³.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 100 | 94 | 95 | 62 | 44 | 32 | 23 | 30 | 36 | 51 | 67 | 83 |
| Level | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Poor | Moderate | Moderate | Moderate | Poor | Poor | Unhealthy | Unhealthy |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 100 | Unhealthy |
| Feb | 94 | Unhealthy |
| Mar | 95 | Unhealthy |
| Apr | 62 | Unhealthy |
| May | 44 | Poor |
| Jun | 32 | Moderate |
| Jul | 23 | Moderate |
| Aug | 30 | Moderate |
| Sep | 36 | Poor |
| Oct | 51 | Poor |
| Nov | 67 | Unhealthy |
| Dec | 83 | Unhealthy |
Growing season
Sylhet 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. Sylhet banks about 5,209 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 229 | 273 | 402 | 452 | 510 | 528 | 558 | 565 | 534 | 503 | 378 | 277 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 229 |
| Feb | 273 |
| Mar | 402 |
| Apr | 452 |
| May | 510 |
| Jun | 528 |
| Jul | 558 |
| Aug | 565 |
| Sep | 534 |
| Oct | 503 |
| Nov | 378 |
| Dec | 277 |
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.
Sylhet receives about 4.1 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 3.1 and 5.4 kWh/m².
The brighter stretch of the year lasts 4.3 months, from around Jan 8 to May 19. The brightest month is March, averaging about 5.3 kWh/m² (bright).
The dimmest month is July, down near 3.2 kWh/m² — roughly 39% less than the March peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 4.2 | 4.8 | 5.3 | 4.9 | 4.2 | 3.3 | 3.2 | 3.5 | 3.6 | 4.1 | 4.2 | 4.0 |
| Level | Bright | Bright | Bright | Bright | Bright | Moderate | Moderate | Moderate | Moderate | Bright | Bright | Moderate |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 4.2 | Bright |
| Feb | 4.8 | Bright |
| Mar | 5.3 | Bright |
| Apr | 4.9 | Bright |
| May | 4.2 | Bright |
| Jun | 3.3 | Moderate |
| Jul | 3.2 | Moderate |
| Aug | 3.5 | Moderate |
| Sep | 3.6 | Moderate |
| Oct | 4.1 | Bright |
| Nov | 4.2 | Bright |
| Dec | 4.0 | Moderate |
Where is Sylhet?
Sylhet sits at 24.9°N, 91.9°E, 26 m above sea level, in Bangladesh. The nearest listed city is Mymensingh, 149 km away.
Topography around Sylhet
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Sylhet.
Within 3 km, the terrain around Sylhet has only modest variations in elevation — a maximum elevation change of 55 m around an average of 19 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 82 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,953 m.
The land around Sylhet is covered by trees (52%) and artificial surfaces (41%) within 3 km, cropland (53%) and trees (39%) within 16 km, and trees (46%) and cropland (40%) within 80 km.
Bangladesh travel facts
- Travel advisory
- Level 3
- Reconsider Travel
- Power plugs
- Type A / C / D / G
- 220 V · 50 Hz
- Prices
- ≈ 25% of US
- price level, 2025
- GDP per capita
- $2,597
- 2025
- Happiness
- 4.3 / 10
- World Happiness, 2025
- Safe drinking water
- 59%
- of population, 2024
- Homicide rate
- 2.3
- per 100k, 2018
- Road deaths
- 15.3
- per 100k/yr, 2019
- Income group
- Lower middle
- World Bank
- English
- Moderate
- EF EPI 506
- 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 Sylhet (24.899°, 91.872°, elevation 26 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. 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).