Nagasaki has a warm temperate climate with warm summers and mild winters.
Nagasaki has an average annual temperature of 17.2°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 33.0°C, while Shimabara is the coldest with average January lows of -3.4°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 | 🌤️ | High | Low | Avg | Humid % | Rain (mm) | Wind (m/s) | Solar (kWh/m²) |
|---|---|---|---|---|---|---|---|---|
| January | 🌤️ | 15.8°C | 0.6°C | 8.2°C | 77% | 67 | 3.6 | 2.20 |
| February | ⛅ | 16.8°C | 1.0°C | 8.9°C | 75% | 87 | 3.5 | 3.00 |
| March | ⛅ | 19.0°C | 3.0°C | 11.0°C | 75% | 136 | 3.3 | 3.90 |
| April | 🌧️ | 22.7°C | 6.7°C | 14.7°C | 77% | 162 | 2.9 | 4.80 |
| May | 🌧️ | 26.0°C | 11.7°C | 18.9°C | 80% | 191 | 2.4 | 5.10 |
| June | 🌧️ | 28.4°C | 16.1°C | 22.2°C | 85% | 320 | 2.2 | 4.60 |
| July | 🌧️ | 31.6°C | 20.8°C | 26.2°C | 87% | 305 | 2.3 | 5.10 |
| August | 🌧️ | 32.7°C | 22.4°C | 27.6°C | 83% | 232 | 2.4 | 5.30 |
| September | 🌧️ | 30.4°C | 18.1°C | 24.3°C | 82% | 201 | 2.8 | 4.30 |
| October | ⛅ | 26.5°C | 12.3°C | 19.4°C | 77% | 95 | 3.0 | 3.70 |
| November | ⛅ | 22.3°C | 6.9°C | 14.6°C | 76% | 95 | 3.1 | 2.60 |
| December | 🌤️ | 18.0°C | 2.4°C | 10.2°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.
🌤️ Early mornings and evenings are most comfortable during this Hot Summer season.
☔ 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
Monthly averages · 1981–2025
💧 Humidity peaks at 87% in July · annual avg 79%
The warmest year on record was 2024 (avg: 18.8°C), while the coldest year was 1986 (avg: 16.1°C).
Averaged across all 20 cities in Nagasaki · Last 10 years · °C
Averaged across all 20 cities in Nagasaki · Last 10 years · mm/year
🔥 hottest · ❄️ coldest · 🌧️ wettest
ℹ️ Values are averages across all 20 cities in Nagasaki for each year.
| Year | Min Temp | Avg Temp | Max Temp | Rainfall (mm) | Avg Humidity | Avg Wind |
|---|---|---|---|---|---|---|
2025 | 10.9°C | 18.0°C | 25.1°C | 2349 | 80% | 2.8 m/s |
2024 🔥 | 12.1°C | 18.8°C | 25.5°C | 2458 | 81% | 2.8 m/s |
2023 | 11.1°C | 18.2°C | 25.3°C | 2350 | 79% | 2.8 m/s |
2022 | 11.0°C | 17.7°C | 24.4°C | 1749 | 78% | 2.9 m/s |
2021 | 11.0°C | 18.1°C | 25.1°C | 2426 | 79% | 2.8 m/s |
2020 | 10.8°C | 17.7°C | 24.5°C | 2592 | 79% | 3.0 m/s |
2019 | 10.8°C | 17.7°C | 24.6°C | 2052 | 78% | 2.7 m/s |
2018 | 10.3°C | 17.7°C | 25.1°C | 1981 | 79% | 2.8 m/s |
2017 | 10.8°C | 17.5°C | 24.1°C | 1810 | 78% | 2.8 m/s |
2016 🌧️ | 10.6°C | 17.8°C | 24.9°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.
