Iwaki, Japan climate
Cfa Humid subtropical
Iwaki has a seasonal mild-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is August with an average daily high near 28°C, while the coldest is January averaging around 0°C at night. Around 1441 mm of precipitation falls each year, peaking in October (193 mm) and easing off in December (51 mm).
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Summers
Warm
Highs near 28°C in August.
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Winters
Cold
Lows near 0°C in January.
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Rain
Wet
About 1441 mm of rain a year.
Wettest in October
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Sky & trend
Often cloudy
Cloudy skies much of the year.
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresHours of sunshine per day
Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER)Iwaki climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 9 | 9 | 12 | 16 | 20 | 23 | 26 | 28 | 25 | 21 | 16 | 11 |
| Avg temp (°C) | 4 | 4 | 7 | 12 | 16 | 19 | 23 | 25 | 22 | 17 | 12 | 7 |
| Avg low (°C) | 0 | 0 | 3 | 7 | 12 | 16 | 20 | 22 | 19 | 13 | 7 | 2 |
| Precipitation (mm) | 57 | 54 | 108 | 125 | 146 | 150 | 161 | 123 | 192 | 193 | 80 | 51 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 9 | 9 | 12 | 16 | 20 | 23 |
| Avg temp (°C) | 4 | 4 | 7 | 12 | 16 | 19 |
| Avg low (°C) | 0 | 0 | 3 | 7 | 12 | 16 |
| Precipitation (mm) | 57 | 54 | 108 | 125 | 146 | 150 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 26 | 28 | 25 | 21 | 16 | 11 |
| Avg temp (°C) | 23 | 25 | 22 | 17 | 12 | 7 |
| Avg low (°C) | 20 | 22 | 19 | 13 | 7 | 2 |
| Precipitation (mm) | 161 | 123 | 192 | 193 | 80 | 51 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 58 | 62 | 65 | 66 | 70 | 80 | 78 | 68 | 74 | 69 | 62 | 57 |
| Relative humidity (%) | 85 | 82 | 80 | 79 | 81 | 84 | 85 | 85 | 86 | 86 | 86 | 86 |
| Wind speed (km/h) | 3.3 | 3.6 | 3.5 | 2.7 | 1.8 | 1.3 | 1.1 | 1.2 | 1.6 | 1.9 | 2.2 | 2.7 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 58 | 62 | 65 | 66 | 70 | 80 |
| Relative humidity (%) | 85 | 82 | 80 | 79 | 81 | 84 |
| Wind speed (km/h) | 3.3 | 3.6 | 3.5 | 2.7 | 1.8 | 1.3 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 78 | 68 | 74 | 69 | 62 | 57 |
| Relative humidity (%) | 85 | 85 | 86 | 86 | 86 | 86 |
| Wind speed (km/h) | 1.1 | 1.2 | 1.6 | 1.9 | 2.2 | 2.7 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from the Japan Meteorological Agency, measured at Onahama, about 12 km from the city centre.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.