Nagasaki has a warm temperate climate with warm summers and mild winters.
Nagasaki has an average annual temperature of 17.0°C across all 20 cities, with approximately 1960 mm of annual precipitation and average humidity of 79%. Temperatures peak in August and drop to their lowest in January, while rainfall is highest during summer months.
The warmest city is Kawatana with average July highs of 29.4°C, while Shimabara is the coldest with average January lows of 0.7°C. Humidity remains high throughout the year creating warm and humid conditions. These seasonal patterns offer comfortable conditions year-round, with warm summers and mild winters.
| Month | 🌤️ | Avg High | Avg Temp | Avg Low | Record High | Record Low | Humid % | Rain (mm) | Wind (m/s) | Solar (kWh/m²) |
|---|---|---|---|---|---|---|---|---|---|---|
| January | 🌤️ | 9.9°C | 7.4°C | 4.9°C | 20.0°C | -6.0°C | 77% | 67 | 3.6 | 2.20 |
| February | ⛅ | 10.8°C | 8.0°C | 5.2°C | 20.5°C | -6.3°C | 75% | 87 | 3.5 | 3.00 |
| March | ⛅ | 13.9°C | 10.8°C | 7.8°C | 23.7°C | -3.2°C | 75% | 136 | 3.3 | 3.90 |
| April | 🌧️ | 18.1°C | 14.8°C | 11.6°C | 28.3°C | -1.2°C | 77% | 162 | 2.9 | 4.80 |
| May | 🌧️ | 21.9°C | 18.7°C | 15.5°C | 31.9°C | 5.3°C | 80% | 191 | 2.4 | 5.10 |
| June | 🌧️ | 25.0°C | 22.3°C | 19.6°C | 32.7°C | 10.3°C | 85% | 320 | 2.2 | 4.60 |
| July | 🌧️ | 28.4°C | 26.1°C | 23.8°C | 35.5°C | 13.8°C | 87% | 305 | 2.3 | 5.10 |
| August | 🌧️ | 29.8°C | 27.4°C | 25.0°C | 37.9°C | 16.0°C | 83% | 232 | 2.4 | 5.30 |
| September | 🌧️ | 26.9°C | 24.5°C | 22.0°C | 37.1°C | 9.0°C | 82% | 201 | 2.8 | 4.30 |
| October | ⛅ | 22.3°C | 19.6°C | 17.0°C | 30.9°C | 2.5°C | 77% | 95 | 3.0 | 3.70 |
| November | ⛅ | 17.3°C | 14.7°C | 12.1°C | 25.9°C | -1.2°C | 76% | 95 | 3.1 | 2.60 |
| December | 🌤️ | 12.2°C | 9.7°C | 7.2°C | 22.5°C | -5.1°C | 76% | 69 | 3.4 | 2.10 |
Showing average climate conditions across 45 years (1981–2025) · averaged across all 20 cities in Nagasaki
🧥 Light layers are sufficient — this Mild Winter stays cool without prolonged hard freezes.
🌤️ 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 20 cities · 1981–2025 · °C
Temperatures rise steadily from spring, peak in August, 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 87% in July · annual avg 79%
Monthly averages · 1981–2025
Across 45 years, Nagasaki's temperature shows a slight warming trend over the past decade. 2024 was the warmest year overall and 1986 the coolest.
The warmest year on record was 2024 (avg: 18.5°C), while the coldest year was 1986 (avg: 16.1°C).
Averaged across all 20 cities in Nagasaki · Last 30 years · °C
Averaged across all 20 cities in Nagasaki · Last 30 years · mm/year
🔥 hottest · ❄️ coldest · 🌧️ wettest
ℹ️ Values are averages across all 20 cities in Nagasaki for each year.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall (mm) | Avg Humidity | Avg Wind |
|---|---|---|---|---|---|---|---|---|
2025 | 20.5°C | 17.9°C | 15.3°C | 35.3°C | -4.5°C | 2349 | 80% | 2.8 m/s |
2024 🔥 | 21.1°C | 18.5°C | 15.9°C | 37.1°C | -3.1°C | 2458 | 81% | 2.8 m/s |
2023 | 20.7°C | 18.1°C | 15.4°C | 36.0°C | -4.8°C | 2350 | 79% | 2.8 m/s |
2022 | 20.3°C | 17.6°C | 14.9°C | 34.3°C | -2.8°C | 1749 | 78% | 2.9 m/s |
2021 | 20.6°C | 17.9°C | 15.1°C | 33.6°C | -3.2°C | 2426 | 79% | 2.8 m/s |
2020 | 20.1°C | 17.4°C | 14.7°C | 37.9°C | -2.5°C | 2592 | 79% | 3.0 m/s |
2019 | 20.4°C | 17.7°C | 14.9°C | 35.2°C | -1.9°C | 2052 | 78% | 2.7 m/s |
2018 | 20.1°C | 17.4°C | 14.6°C | 35.5°C | -5.1°C | 1981 | 79% | 2.8 m/s |
2017 | 19.7°C | 17.1°C | 14.4°C | 35.1°C | -2.5°C | 1810 | 78% | 2.8 m/s |
2016 🌧️ | 20.4°C | 17.7°C | 15.0°C | 35.2°C | -4.8°C | 2619 | 80% | 2.8 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.
