Climate averages 1991–2020
Siwān weather
in September.
A hot, very wet month: the 7th warmest and the 10th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Siwān: daytime highs average 30.9°C and nights cool to about 25.0°C. By daytime temperature it is the 7th warmest of the 12 months.
Expect about 205 mm of rain on roughly 21 days, which makes September a very wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 20 min on an average September day.
The nearest other city in this atlas is Chāpra (63 km away). In September its highs average 31.0°C, about as warm as Siwān, with 191 mm of rain.
Among the 692 cities listed in India, Siwān ranks joint 315th of 692 for the warmest September highs and joint 521st of 692 for the driest September (rainfall, lowest first). The mean September high of those 692 cities is 30.7°C; Siwān is 0.2°C warmer than that mean.
From September to October, average highs fall by 0.6°C to 30.2°C, and monthly rainfall falls from 205 mm to 37 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Siwān climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 21.8°C10.3°C | 10.3°C | 16 | 2.2 | 10.711 h |
| February | 25.7°C13.2°C | 13.2°C | 17 | 2.4 | 11.311 h |
| March | 32.0°C18.2°C | 18.2°C | 12 | 2.1 | 12.012 h |
| April | 37.1°C23.3°C | 23.3°C | 10 | 2.5 | 12.813 h |
| May | 37.6°C26.1°C | 26.1°C | 29 | 5.2 | 13.413 h |
| June | 35.6°C27.0°C | 27.0°C | 180 | 15.5 | 13.814 h |
| July | 31.9°C26.3°C | 26.3°C | 329 | 26.0 | 13.614 h |
| August | 31.5°C26.0°C | 26.0°C | 294 | 26.6 | 13.113 h |
| September, selected | 30.9°C25.0°C | 25.0°C | 205 | 20.5 | 12.312 h |
| October | 30.2°C21.3°C | 21.3°C | 37 | 4.3 | 11.612 h |
| November | 27.8°C16.0°C | 16.0°C | 4.5 | 0.4 | 10.911 h |
| December | 23.7°C11.8°C | 11.8°C | 7.6 | 0.7 | 10.511 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
- Chāpra in SeptemberIndia · 63 kmHigh 31.0°C · Low 25.3°C · 191 mm rain
- Deoria in SeptemberIndia · 65 kmHigh 30.9°C · Low 24.9°C · 217 mm rain
- Bettiah in SeptemberIndia · 66 kmHigh 30.8°C · Low 24.8°C · 237 mm rain
- Mothīhāri in SeptemberIndia · 73 kmHigh 30.8°C · Low 24.9°C · 292 mm rain
- Kushinagar in SeptemberIndia · 74 kmHigh 30.8°C · Low 24.8°C · 213 mm rain
- Arrah in SeptemberIndia · 80 kmHigh 31.0°C · Low 25.3°C · 197 mm rain
- Buxar in SeptemberIndia · 81 kmHigh 31.1°C · Low 25.2°C · 207 mm rain
- Mau in SeptemberIndia · 85 kmHigh 31.0°C · Low 25.0°C · 208 mm rain
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 limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Siwān) is explained once on the Siwān year overview and on the Sources, method and limits page.