Bihar has a warm subtropical climate with warm summers and mild winters.
Bihar has an average annual temperature of 26.3°C across all 37 cities, with approximately 1049 mm of annual precipitation and average humidity of 56%. Temperatures peak in May and drop to their lowest in January, while rainfall is highest during summer months.
The warmest city is Buxar with average July highs of 39.2°C, while Siwan is the coldest with average January lows of 4.9°C. Humidity remains moderate throughout the year, especially in autumn, creating warm and dry conditions. These seasonal patterns offer comfortable conditions year-round, with warm summers and mild winters.
| Month | 🌤️ | High | Low | Avg | Humid % | Rain (mm) | Wind (m/s) | Solar (kWh/m²) |
|---|---|---|---|---|---|---|---|---|
| January | ☀️ | 28.3°C | 5.5°C | 16.9°C | 49% | 9 | 1.6 | 3.40 |
| February | ☀️ | 33.4°C | 7.8°C | 20.6°C | 40% | 12 | 1.8 | 4.60 |
| March | 😎 | 39.8°C | 12.3°C | 26.0°C | 30% | 13 | 2.1 | 5.80 |
| April | 🥵 | 43.5°C | 18.8°C | 31.2°C | 27% | 21 | 2.3 | 6.40 |
| May | 🥵 | 44.9°C | 23.3°C | 34.1°C | 37% | 60 | 2.4 | 6.40 |
| June | 🌧️ | 44.0°C | 25.9°C | 35.0°C | 53% | 154 | 2.7 | 5.60 |
| July | 🌧️ | 37.6°C | 25.2°C | 31.4°C | 77% | 289 | 2.6 | 4.70 |
| August | 🌧️ | 34.9°C | 24.6°C | 29.7°C | 84% | 242 | 2.2 | 4.70 |
| September | 🌧️ | 33.8°C | 22.4°C | 28.1°C | 84% | 184 | 1.9 | 4.60 |
| October | 😎 | 32.9°C | 16.1°C | 24.5°C | 74% | 56 | 1.3 | 4.70 |
| November | ☀️ | 30.8°C | 11.0°C | 20.9°C | 62% | 5 | 1.2 | 4.10 |
| December | ☀️ | 27.7°C | 6.7°C | 17.2°C | 56% | 6 | 1.4 | 3.40 |
Showing average climate conditions across 45 years (1981–2025) · averaged across all 37 cities in Bihar
🧥 Light layers are sufficient — this Mild Winter stays cool without prolonged hard freezes.
🌤️ Limit midday outdoor exposure and stay hydrated — this is an intense Hot Summer.
☔ Heavy Rainfall expected — carry rain gear and plan outdoor activities around these months.
Region-wide monthly averages across 37 cities · 1981–2025 · °C
Temperatures rise steadily from spring, peak in May, and gradually decline through autumn into winter.
These seasonal patterns offer comfortable conditions year-round, with warm summers and mild winters.
Region-wide monthly rainfall · 1981–2025 · mm/month
Monthly averages · 1981–2025
💧 Humidity peaks at 84% in September · annual avg 56%
The warmest year on record was 1992 (avg: 27.3°C), while the coldest year was 2020 (avg: 25.0°C).
Averaged across all 37 cities in Bihar · Last 10 years · °C
Averaged across all 37 cities in Bihar · Last 10 years · mm/year
🔥 hottest · ❄️ coldest · 🌧️ wettest
ℹ️ Values are averages across all 37 cities in Bihar for each year.
| Year | Min Temp | Avg Temp | Max Temp | Rainfall (mm) | Avg Humidity | Avg Wind |
|---|---|---|---|---|---|---|
2025 | 17.3°C | 26.3°C | 35.2°C | 1203 | 63% | 2.0 m/s |
2024 | 17.3°C | 26.7°C | 36.1°C | 1112 | 61% | 2.1 m/s |
2023 | 17.7°C | 26.9°C | 36.1°C | 1180 | 58% | 2.0 m/s |
2022 | 17.0°C | 26.2°C | 35.3°C | 1020 | 64% | 2.0 m/s |
2021 | 16.5°C | 25.6°C | 34.6°C | 1561 | 65% | 1.9 m/s |
2020 🌧️ | 16.0°C | 25.0°C | 34.0°C | 1565 | 68% | 1.8 m/s |
2019 | 16.6°C | 26.5°C | 36.3°C | 1107 | 60% | 2.0 m/s |
2018 | 17.5°C | 26.9°C | 36.3°C | 822 | 54% | 2.0 m/s |
2017 | 17.0°C | 26.7°C | 36.3°C | 1080 | 59% | 1.9 m/s |
2016 | 17.8°C | 27.1°C | 36.4°C | 1127 | 57% | 1.9 m/s |
Showing 1 to 10 of 45 years
All weather data is sourced from NASA POWER (Prediction of Worldwide Energy Resources), a NASA project providing solar and meteorological data for renewable energy, building efficiency, and agricultural research.
