Nagano has a temperate climate with warm summers and freezing winters.
Nagano has an average annual temperature of 9.1°C across all 40 cities, with approximately 1391 mm of annual precipitation and average humidity of 83%. Temperatures peak in August and drop to their lowest in February, while rainfall is highest during autumn months.
The warmest city is Sakuho with average July highs of 30.6°C, while Iijima is the coldest with average January lows of -15.2°C. Humidity remains high throughout the year, especially during winter months, creating cold and damp conditions. These seasonal patterns make summer ideal for outdoor activities, while winters bring freezing conditions and heavy snowfall.
| Month | 🌤️ | High | Low | Avg | Humid % | Rain (mm) | Wind (m/s) | Solar (kWh/m²) |
|---|---|---|---|---|---|---|---|---|
| January | ❄️ | 5.8°C | -13.6°C | -3.9°C | 88% | 68 | 2.5 | 2.30 |
| February | ❄️ | 8.4°C | -13.6°C | -2.6°C | 86% | 64 | 2.6 | 3.10 |
| March | ⛅ | 14.2°C | -9.9°C | 2.1°C | 81% | 94 | 2.5 | 4.00 |
| April | ⛅ | 20.4°C | -5.1°C | 7.6°C | 77% | 96 | 2.2 | 4.80 |
| May | ⛅ | 24.0°C | 0.0°C | 12.0°C | 76% | 112 | 1.9 | 5.20 |
| June | 🌧️ | 26.5°C | 6.7°C | 16.6°C | 80% | 154 | 1.5 | 4.70 |
| July | 🌧️ | 28.8°C | 12.7°C | 20.8°C | 82% | 181 | 1.5 | 4.70 |
| August | 🌧️ | 29.5°C | 13.6°C | 21.5°C | 82% | 155 | 1.4 | 4.80 |
| September | 🌧️ | 27.3°C | 7.4°C | 17.3°C | 84% | 183 | 1.5 | 3.80 |
| October | ⛅ | 22.5°C | 0.0°C | 11.2°C | 84% | 134 | 1.6 | 3.20 |
| November | ⛅ | 16.8°C | -4.4°C | 6.2°C | 85% | 82 | 1.9 | 2.60 |
| December | 🌤️ | 10.8°C | -10.2°C | 0.3°C | 86% | 69 | 2.3 | 2.10 |
Showing average climate conditions across 45 years (1981–2025) · averaged across all 40 cities in Nagano
🧥 Pack heavy layers and prepare for snow — this is a Severe Winter destination.
🌤️ Conditions are ideal for outdoor activities throughout the day in this Mild Summer.
☔ Heavy Rainfall expected — carry rain gear and plan outdoor activities around these months.
Region-wide monthly averages across 40 cities · 1981–2025 · °C
Temperatures rise steadily from spring, peak in August, and gradually decline through autumn into winter.
These seasonal patterns make summer ideal for outdoor activities, while winters bring freezing conditions and heavy snowfall.
Region-wide monthly rainfall · 1981–2025 · mm/month
Monthly averages · 1981–2025
💧 Humidity peaks at 88% in January · annual avg 83%
The warmest year on record was 2024 (avg: 10.8°C), while the coldest year was 1981 (avg: 7.8°C).
Averaged across all 40 cities in Nagano · Last 10 years · °C
Averaged across all 40 cities in Nagano · Last 10 years · mm/year
🔥 hottest · ❄️ coldest · 🌧️ wettest
ℹ️ Values are averages across all 40 cities in Nagano for each year.
| Year | Min Temp | Avg Temp | Max Temp | Rainfall (mm) | Avg Humidity | Avg Wind |
|---|---|---|---|---|---|---|
2025 | -0.2°C | 10.3°C | 20.7°C | 1493 | 84% | 1.9 m/s |
2024 🌧️ | 0.6°C | 10.8°C | 20.9°C | 1860 | 84% | 1.9 m/s |
2023 | 0.4°C | 10.8°C | 21.2°C | 1492 | 81% | 1.9 m/s |
2022 | -0.5°C | 9.6°C | 19.6°C | 1505 | 84% | 1.9 m/s |
2021 | -0.2°C | 9.8°C | 19.8°C | 1610 | 83% | 2.0 m/s |
2020 | 0.3°C | 10.2°C | 20.1°C | 1602 | 83% | 1.9 m/s |
2019 | 0.3°C | 10.4°C | 20.5°C | 1482 | 82% | 1.9 m/s |
2018 | -0.7°C | 10.2°C | 21.0°C | 1441 | 82% | 2.0 m/s |
2017 | -1.0°C | 9.0°C | 18.9°C | 1406 | 82% | 2.0 m/s |
2016 | -1.1°C | 9.5°C | 20.1°C | 1485 | 83% | 1.8 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.
