Weather in Siwān, Bihar
Located in Bihar, India, Siwān is a growing city in the semi-arid to humid subtropical climate zone, at about 26.2°N latitude.
Climate Overview
Central India receives substantial monsoon rainfall from June to September, with the Western Ghats creating a rain shadow effect on the eastern side. Temperatures in Siwān range from moderate winters to warm or hot summers, depending on elevation and proximity to the coast. Weather here is dominated by seasonal monsoon patterns, which bring the bulk of annual rainfall.
Weather by season in Siwān
Siwān's year divides into four broad seasons. The southwest monsoon normally arrives around 23 June. Daytime figures below are typical lowland values for this latitude — hill stations sit markedly cooler.
- Winter (Dec–Feb): days around 26°C, nights around 10°C. Dry and clear, with cold mornings and occasional fog.
- Summer / pre-monsoon (Mar–Jun): days around 42°C, nights around 27°C. Hot, dry and dusty — heatwave conditions are common at the peak.
- Monsoon (Jul–Sep): days around 33°C, nights around 25°C. Frequent rain and high humidity; the wettest part of the year.
- Post-monsoon (Oct–Nov): days around 32°C, nights around 18°C. Skies clear and temperatures ease — comfortable and settled.
Today's Weather in Siwān
The current weather conditions in Siwān are updated every hour from the ECMWF global model via Open-Meteo. You can see real-time temperature, humidity, wind speed and air quality at the top of this page.
Hourly Forecast
Planning your day in Siwān? The 24-hour forecast shows temperature changes, precipitation probability and wind conditions for each hour, helping you pick the best time for travel, outdoor work or events in Bihar.
7-Day Weather Forecast for Siwān
Tomorrow's weather, the day after and the full week ahead for Siwān are summarised in the 7-day outlook. Rain, cloud cover and wind direction are all shown.
Air Quality in Siwān
Air quality in Siwān is measured using the European Air Quality Index, with PM2.5 and PM10 particulate matter readings displayed alongside the live forecast. Siwān typically enjoys cleaner air than the major metros, though pre-monsoon dust and winter fog can push AQI into the moderate range.
Quick facts about Siwān
Siwān has a population of about 1,35,066; sits at 26.22°N; and is in India; its monsoon typically arrives in mid-June.
Common spellings
The Hindi word for weather, मौसम, is transliterated in many ways: mausam, mosam, mausham, musam, mosum, moshm, mausm. All refer to the same concept — the current weather conditions, today's temperature and the forecast you'll find for Siwān on this page.
Nearby Cities in Bihar
Explore weather forecasts for other cities in Bihar. See the "More in Bihar" section above, or browse the full list on our states page.