Climate averages 1991–2020

Sylhet weather
in September.

A hot, very wet month: the joint 2nd warmest and the 7th driest of the year.

Long-term climate patterns, not a forecast for a particular trip.

Average high 30.1°C Daytime mean, September

Average low 24.5°C Night-time mean, September

Rainfall 523 mm 28 days with ≥1 mm

Daylight 12 h Sunrise to sunset, per day

September is a hot month in Sylhet: daytime highs average 30.1°C and nights cool to about 24.5°C. By daytime temperature it is the joint 2nd warmest of the 12 months.

Expect about 523 mm of rain on roughly 28 days, which makes September a very wet month (the 7th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 19 min on an average September day.

The nearest other city in this atlas is Sunāmganj (51 km away). In September its highs average 29.2°C, 0.9°C cooler than Sylhet, with 521 mm of rain.

Among the 63 cities listed in Bangladesh, Sylhet ranks joint 54th of 63 for the warmest September highs and 63rd of 63 for the driest September (rainfall, lowest first). The mean September high of those 63 cities is 30.5°C; Sylhet is 0.4°C cooler than that mean.

From September to October, average highs fall by 0.8°C to 29.3°C, and monthly rainfall falls from 523 mm to 217 mm.

The annual picture

September in context

30-year average

Average highAverage low°C

Monthly rainfall

Average total · mm

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Sylhet climate table

1991–2020

Monthly climate averages for Sylhet, 1991–2020
Month	Average highHigh / low	Average low	Rainfall mm/month	Rain days ≥1 mm/day	Daylight hours/dayDaylight h/day
January	23.5°C11.6°C	11.6°C	10	1.8	10.811 h
February	25.8°C13.7°C	13.7°C	48	4.7	11.311 h
March	28.6°C17.4°C	17.4°C	186	11.2	12.012 h
April	29.4°C20.9°C	20.9°C	559	21.4	12.713 h
May	29.8°C23.1°C	23.1°C	759	27.6	13.313 h
June	30.0°C24.7°C	24.7°C	953	29.5	13.714 h
July	30.1°C25.0°C	25.0°C	940	30.8	13.514 h
August	30.4°C25.1°C	25.1°C	733	30.7	13.013 h
September, selected	30.1°C24.5°C	24.5°C	523	27.6	12.312 h
October	29.3°C22.1°C	22.1°C	217	14.8	11.612 h
November	27.3°C17.3°C	17.3°C	28	2.3	11.011 h
December	24.7°C13.3°C	13.3°C	12	1.0	10.611 h

Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

September in nearby cities

Distance from Sylhet

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Sylhet) is explained once on the Sylhet year overview and on the Sources, method and limits page.