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
💧 Humidity peaks at 84% in September · annual avg 56%
Monthly averages · 1981–2025
Across 45 years, Bihar's temperature has remained relatively stable over the past decade. 1992 was the warmest year overall and 2020 the coolest.
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 30 years · °C
Averaged across all 37 cities in Bihar · Last 30 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.
