Nagano has a temperate climate with warm summers and cold winters.
Nagano has an average annual temperature of 8.9°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 January, while rainfall is highest during autumn months.
The warmest city is Sakuho with average July highs of 26.7°C, while Iijima is the coldest with average January lows of -9.3°C. Humidity remains high throughout the year, especially during winter months, creating cold and damp conditions. These seasonal patterns make summer pleasant for travel, while winters can bring frost and occasional snowfall.
| Month | 🌤️ | Avg High | Avg Temp | Avg Low | Record High | Record Low | Humid % | Rain (mm) | Wind (m/s) | Solar (kWh/m²) |
|---|---|---|---|---|---|---|---|---|---|---|
| January | ❄️ | 0.1°C | -4.1°C | -8.4°C | 13.8°C | -19.1°C | 88% | 68 | 2.5 | 2.30 |
| February | ❄️ | 1.2°C | -3.5°C | -8.1°C | 17.1°C | -20.7°C | 86% | 64 | 2.6 | 3.10 |
| March | ⛅ | 6.0°C | 0.9°C | -4.2°C | 21.1°C | -17.3°C | 81% | 94 | 2.5 | 4.00 |
| April | ⛅ | 13.1°C | 7.0°C | 1.0°C | 25.2°C | -10.3°C | 77% | 96 | 2.2 | 4.80 |
| May | ⛅ | 18.4°C | 12.5°C | 6.6°C | 29.1°C | -4.9°C | 76% | 112 | 1.9 | 5.20 |
| June | 🌧️ | 21.9°C | 17.0°C | 12.0°C | 33.7°C | 1.7°C | 80% | 154 | 1.5 | 4.70 |
| July | 🌧️ | 25.4°C | 21.0°C | 16.5°C | 34.4°C | 6.8°C | 82% | 181 | 1.5 | 4.70 |
| August | 🌧️ | 26.5°C | 22.0°C | 17.5°C | 36.9°C | 6.9°C | 82% | 155 | 1.4 | 4.80 |
| September | 🌧️ | 22.6°C | 18.0°C | 13.4°C | 32.6°C | -0.3°C | 84% | 183 | 1.5 | 3.80 |
| October | ⛅ | 16.4°C | 11.5°C | 6.6°C | 27.9°C | -5.2°C | 84% | 134 | 1.6 | 3.20 |
| November | ⛅ | 10.2°C | 5.3°C | 0.5°C | 22.6°C | -8.7°C | 85% | 82 | 1.9 | 2.60 |
| December | ❄️ | 3.6°C | -0.6°C | -4.7°C | 19.6°C | -16.9°C | 86% | 69 | 2.3 | 2.10 |
Showing average climate conditions across 45 years (1981–2025) · averaged across all 40 cities in Nagano
🧥 Expect frosty nights and below-freezing temperatures during this Cold Winter period.
🌤️ 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 pleasant for travel, while winters can bring frost and occasional snowfall.
Region-wide monthly rainfall · 1981–2025 · mm/month
💧 Humidity peaks at 88% in January · annual avg 83%
Monthly averages · 1981–2025
Across 45 years, Nagano's temperature shows a slight warming trend over the past decade. 2024 was the warmest year overall and 1984 the coolest.
The warmest year on record was 2024 (avg: 10.7°C), while the coldest year was 1984 (avg: 7.6°C).
Averaged across all 40 cities in Nagano · Last 30 years · °C
Averaged across all 40 cities in Nagano · Last 30 years · mm/year
🔥 hottest · ❄️ coldest · 🌧️ wettest
ℹ️ Values are averages across all 40 cities in Nagano for each year.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall (mm) | Avg Humidity | Avg Wind |
|---|---|---|---|---|---|---|---|---|
2025 | 14.7°C | 10.1°C | 5.4°C | 32.3°C | -15.1°C | 1493 | 84% | 1.9 m/s |
2024 🌧️ | 15.2°C | 10.7°C | 6.2°C | 32.7°C | -13.3°C | 1860 | 84% | 1.9 m/s |
2023 🔥 | 15.3°C | 10.5°C | 5.6°C | 31.9°C | -16.1°C | 1492 | 81% | 1.9 m/s |
2022 | 14.1°C | 9.5°C | 4.9°C | 31.4°C | -17.4°C | 1505 | 84% | 1.9 m/s |
2021 | 14.4°C | 9.7°C | 5.0°C | 31.9°C | -14.2°C | 1610 | 83% | 2.0 m/s |
2020 | 14.4°C | 9.8°C | 5.2°C | 32.1°C | -14.6°C | 1602 | 83% | 1.9 m/s |
2019 | 14.4°C | 9.7°C | 5.0°C | 31.5°C | -13.8°C | 1482 | 82% | 1.9 m/s |
2018 | 14.5°C | 9.7°C | 4.8°C | 32.6°C | -15.9°C | 1441 | 82% | 2.0 m/s |
2017 | 13.3°C | 8.6°C | 3.9°C | 30.8°C | -14.9°C | 1406 | 82% | 2.0 m/s |
2016 | 14.5°C | 9.7°C | 4.8°C | 31.2°C | -18.8°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.
