Patna: Bihar is likely to experience a milder start to winter this December, with warmer-than-usual daytime temperatures and patchy chilly nights across parts of the state, according to the India Meteorological Department’s monthly forecast bulletin for December 2025. The bulletin, issued by the Patna Meteorological Centre, also indicates a higher probability of above-normal rainfall in several districts.
Warmer days across most of Bihar
The IMD projects that maximum temperatures will remain above normal across most of Bihar through December. The bulletin notes that the state’s typical December maximum temperature ranges between 22°C and 24°C, but this year, a higher-than-usual temperature anomaly is expected.
This comes after unusually warm conditions in November, when Patna recorded an average maximum of 28°C, and Motihari logged the state’s highest single-day temperature of 34.5°C on November 6.
Cold nights in some eastern and south-eastern districts
While daytime temperatures may be higher than normal, minimum temperatures are projected to remain average or slightly above normal, particularly in parts of north-eastern and south-eastern Bihar. Typical December nights fall between 10°C and 12°C.
The forecast suggests only limited pockets may see below-normal lows, reducing the likelihood of severe early-winter chills.
— Mausam Bihar- IMD Patna (@imd_patna) December 2, 2025
Cold-wave days to remain normal
Despite temperature swings, cold-wave conditions are expected to remain close to normal levels, the IMD says. The forecast bulletin further states that no significant rise in cold-wave frequency for December, suggesting winter severity will neither sharply increase nor diminish compared with climatological averages.
Rainfall likely to be normal to above normal
The bulletin forecasts normal or above-normal rainfall across most regions of the state. Bihar typically receives 5.1 mm of rainfall in December, but several districts may surpass this, driven by local weather systems.
In November, rainfall had already exceeded seasonal expectations, with statewide totals reaching 169% above normal, supported by heavy single-day events such as 170 mm in Khagaria’s Baltara on November 1.
Fog set to remain a major concern
While the bulletin focuses on temperature and rainfall, the early winter pattern—marked by steady moisture and cooling nights—suggests that fog formation will intensify, particularly across northern districts. Reduced visibility has already disrupted transport in the past week, and conditions may persist or worsen into the first half of December.
What this means for Bihar
- Days will feel warmer than usual, delaying peak winter chill.
- Nights may vary, remaining mild in many regions but dropping slightly in pockets of the east.
- Fog is likely to remain widespread, affecting travel and transport.
- Rainfall could surprise, with several districts expected to receive more showers than usual.
- Cold-wave events will stay within the normal seasonal range, signalling no extreme winter anomalies.
As December progresses, IMD officials advise residents—especially commuters and farmers—to monitor daily forecasts closely, as fog and temperature variations may influence transport, crop planning and public health.
