Yanai has a warm temperate climate with warm summers and cold winters.
Temperatures peak in August and drop to their lowest in January, while rainfall is highest during summer months.
Humidity remains high throughout the year creating cold and damp conditions.
| Month | 🌤️ | High | Low | Avg | Humid % | Rain (mm) | Wind (m/s) | Solar (kWh/m²) |
|---|---|---|---|---|---|---|---|---|
| January | 🌨️ | 14.0°C | -0.7°C | 6.6°C | 76% | 58 | 2.9 | 2.40 |
| February | 🌨️ | 15.1°C | -0.3°C | 7.4°C | 75% | 73 | 2.8 | 3.16 |
| March | ☔ | 18.1°C | 1.6°C | 9.8°C | 76% | 118 | 2.4 | 4.06 |
| April | ☔ | 22.0°C | 4.7°C | 13.4°C | 77% | 134 | 1.9 | 4.98 |
| May | 🌧️ | 25.6°C | 9.9°C | 17.8°C | 79% | 157 | 1.6 | 5.28 |
| June | 🌧️ | 28.4°C | 14.7°C | 21.6°C | 83% | 251 | 1.3 | 4.69 |
| July | 🌧️ | 31.7°C | 19.9°C | 25.8°C | 85% | 248 | 1.3 | 5.23 |
| August | 🌧️ | 32.4°C | 21.4°C | 26.9°C | 83% | 156 | 1.6 | 5.29 |
| September | 🌧️ | 30.2°C | 16.7°C | 23.4°C | 81% | 176 | 1.9 | 4.25 |
| October | ☔ | 25.7°C | 10.9°C | 18.3°C | 77% | 96 | 2.2 | 3.59 |
| November | 🌤️ | 21.5°C | 5.8°C | 13.6°C | 76% | 74 | 2.4 | 2.70 |
| December | 🌨️ | 16.7°C | 1.4°C | 9.0°C | 77% | 57 | 2.8 | 2.18 |
Showing average climate conditions across 45 years (1981–2025)
🧥 Expect frosty nights and below-freezing temperatures during this Cold Winter period.
🌤️ 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.
Monthly averages · 1981–2025 climate normals · °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.
Monthly rainfall · 1981–2025 seasonal trends · mm/month
Monthly averages · 1981–2025
💧 Humidity peaks at 85% in July · annual avg 79%
The warmest year in Yanai's recorded history was 2024 (avg: 17.6°C), while the coldest was 1986 (avg: 15.2°C).
Average annual high/low · Last 10 years · °C
Total annual precipitation · Last 10 years · mm/year
| Year | Min Temp | Avg Temp | Max Temp | Rainfall (mm) | Avg Humidity | Avg Wind |
|---|---|---|---|---|---|---|
2025 | 9.4°C | 16.7°C | 24.1°C | 1916 | 80% | 2.0 m/s |
2024 🔥 🌧️ | 10.5°C | 17.6°C | 24.7°C | 2190 | 81% | 2.0 m/s |
2023 | 9.9°C | 17.3°C | 24.6°C | 1978 | 80% | 1.9 m/s |
2022 | 9.2°C | 16.3°C | 23.3°C | 1403 | 78% | 2.0 m/s |
2021 | 9.2°C | 16.4°C | 23.7°C | 2002 | 80% | 2.0 m/s |
2020 | 9.6°C | 16.5°C | 23.3°C | 1962 | 79% | 2.1 m/s |
2019 | 9.7°C | 16.9°C | 24.0°C | 1643 | 79% | 2.0 m/s |
2018 | 8.6°C | 16.3°C | 24.0°C | 1801 | 80% | 2.0 m/s |
2017 | 9.1°C | 16.0°C | 22.9°C | 1670 | 79% | 2.1 m/s |
2016 | 9.2°C | 16.7°C | 24.1°C | 2187 | 81% | 2.0 m/s |
Showing 1 to 10 of 45 years
Based on 45 years of data (1981–2025), August is typically the hottest month in Yanai, Yamaguchi, with average high temperatures around 32.4°C.
January is the coldest month in Yanai, with average low temperatures around -0.7°C.
June receives the most rainfall with approximately 251 mm, while December is the driest with 57 mm.
The highest recorded temperature was 35.5°C in July 1994. This is part of the historical record spanning 1981–2025.
The lowest recorded temperature was -5.9°C in February 1981.
This page covers 45 years of climate data from 1981 to 2025. As new data is added to the database the page automatically reflects the updated coverage.
Yanai receives the most sunlight in August with an average solar radiation of 5.29 kWh/m²/day. This solar radiation data, sourced from NASA POWER, is useful for solar energy planning and agriculture in Yamaguchi.
All climate data is sourced from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite and model data. It provides monthly averages for temperature, precipitation, humidity, wind speed, and solar radiation.
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.
