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Iwaki, Fukushima Weather by Month and Climate Averages
Monthly normals · Rain · Snow
Sunshine · Freeze dates · Records · Best time to visit
What is the weather like in Iwaki, Fukushima?
Iwaki, Fukushima gets 1323 mm of precipitation a year over about 100 rainy days. August is the warmest month (average high 28°C) and January the coldest (average low -1°C).
Humid subtropical climate
Iwaki, Fukushima has warm summers and chilly winters. Daytime highs range from about 9°C in January to 28°C in August. October is usually the wettest month. The most comfortable time to visit is typically May to July and September, when daytime highs sit near 24°C.
| Season | Months | Avg low | Avg high |
|---|---|---|---|
| Winter | Dec–Feb | 0° | 9° |
| Spring | Mar–May | 7° | 16° |
| Summer | Jun–Aug | 19° | 26° |
| Autumn | Sep–Nov | 12° | 21° |
How much rain does Iwaki get?
Iwaki gets 1323 mm of precipitation in an average year, spread over about 100 days with measurable rain. That is fewer rainy days than 76% of Japan.
October is the wettest month, with 186 mm. February is the driest, with 47 mm. July has the most rainy days, about 12.
The longest dry spell in the last five years lasted 29 days, to February 9, 2022.
From October 2025 to September 2026 Iwaki got 1561 mm of rain, against a normal of 1323 mm for those months. August 2026 had the most, with 906 mm.
Iwaki weather by month
Iwaki weather in January
In January, Iwaki averages a high of 9°C and a low of -1°C. It gets 50 mm of precipitation over about 5 rainy days. Estimated sunshine is 57% of daylight hours, derived from ERA5 cloud cover. The January record high is 18°C (2010) and the record low is -8°C (1970).
Iwaki weather in February
In February, Iwaki averages a high of 9°C and a low of -1°C. It gets 47 mm of precipitation over about 5 rainy days. Estimated sunshine is 55% of daylight hours, derived from ERA5 cloud cover. The February record high is 22°C (2024) and the record low is -8°C (1977).
Iwaki weather in March
In March, Iwaki averages a high of 12°C and a low of 2°C. It gets 94 mm of precipitation over about 8 rainy days. Estimated sunshine is 44% of daylight hours, derived from ERA5 cloud cover. The March record high is 23°C (2007) and the record low is -7°C (1977).
Iwaki weather in April
In April, Iwaki averages a high of 16°C and a low of 7°C. It gets 113 mm of precipitation over about 9 rainy days. Estimated sunshine is 42% of daylight hours, derived from ERA5 cloud cover. The April record high is 27°C (2004) and the record low is -2°C (1981).
Iwaki weather in May
In May, Iwaki averages a high of 20°C and a low of 12°C. It gets 136 mm of precipitation over about 10 rainy days. Estimated sunshine is 32% of daylight hours, derived from ERA5 cloud cover. The May record high is 30°C (2026) and the record low is 3°C (1991). May is one of the most comfortable months to visit.
Iwaki weather in June
In June, Iwaki averages a high of 23°C and a low of 16°C. It gets 145 mm of precipitation over about 11 rainy days. Estimated sunshine is 26% of daylight hours, derived from ERA5 cloud cover. The June record high is 33°C (2025) and the record low is 8°C (2010). June is one of the most comfortable months to visit.
Iwaki weather in July
In July, Iwaki averages a high of 26°C and a low of 20°C. It gets 142 mm of precipitation over about 12 rainy days. Estimated sunshine is 25% of daylight hours, derived from ERA5 cloud cover. The July record high is 37°C (2024) and the record low is 9°C (1976). July is one of the most comfortable months to visit.
Iwaki weather in August
In August, Iwaki averages a high of 28°C and a low of 22°C. It gets 118 mm of precipitation over about 9 rainy days. Estimated sunshine is 37% of daylight hours, derived from ERA5 cloud cover. The August record high is 38°C (1994) and the record low is 13°C (1980).
Iwaki weather in September
In September, Iwaki averages a high of 26°C and a low of 18°C. It gets 172 mm of precipitation over about 10 rainy days. Estimated sunshine is 29% of daylight hours, derived from ERA5 cloud cover. The September record high is 34°C (1992) and the record low is 9°C (2001). September is one of the most comfortable months to visit.
Iwaki weather in October
In October, Iwaki averages a high of 21°C and a low of 12°C. It gets 186 mm of precipitation over about 9 rainy days. Estimated sunshine is 40% of daylight hours, derived from ERA5 cloud cover. The October record high is 32°C (2018) and the record low is 2°C (1984).
Iwaki weather in November
In November, Iwaki averages a high of 16°C and a low of 6°C. It gets 73 mm of precipitation over about 7 rainy days. Estimated sunshine is 57% of daylight hours, derived from ERA5 cloud cover. The November record high is 25°C (1977) and the record low is -3°C (1983).
Iwaki weather in December
In December, Iwaki averages a high of 11°C and a low of 2°C. It gets 47 mm of precipitation over about 5 rainy days. Estimated sunshine is 62% of daylight hours, derived from ERA5 cloud cover. The December record high is 26°C (2004) and the record low is -6°C (1973).
Sunshine, humidity and wind in Iwaki
December is the sunniest month in Iwaki, with estimated sunshine of 62% of daylight hours from ERA5 cloud cover. July is the cloudiest, at 25%. The annual cloud-cover estimate is 42% of daylight hours; it is not a measurement of sunshine duration. Iwaki is sunnier than 83% of Japan.
Humidity peaks in July at 90% and is lowest in February at 62%.
Iwaki has about 3 days a year above 32°C. Iwaki is cooler than 88% of Japan.
First and last freeze in Iwaki
The first fall freeze in Iwaki typically comes around December 5, and the last spring freeze around March 27. That leaves a frost-free growing season of about 253 days.
Iwaki weather records
These records cover ONAHAMA during 1970–2026. Earlier records or other stations in the city may differ.
The hottest temperature on record at the Iwaki station is 38°C, on August 3, 1994. The coldest is -8°C, on January 30, 1985.
The wettest day in the available station history brought 269 mm of precipitation, on August 6, 2026.
30 all-time records have been set at the station since 1970.
The best time to visit Iwaki
The most comfortable time to visit is typically May to July and September, when daytime highs sit near 24°C.
Winter (December–February) is chilly, with average highs around 10°C and lows near 0°C.
Spring (March–May) is mild, with average highs around 16°C and lows near 7°C.
Summer (June–August) is warm, with average highs around 26°C and lows near 19°C. It can feel humid.
Autumn (September–November) is warm, with average highs around 21°C and lows near 12°C.
Monthly climate
| Month | Average low | Average high | Precip | Rain days | Humidity | Estimated sunshine | Record high | Record low |
|---|---|---|---|---|---|---|---|---|
| January | -1° | 9° | 50 mm | 5 | 63% | 57% | 18° | -8° |
| February | -1° | 9° | 47 mm | 5 | 62% | 55% | 22° | -8° |
| March | 2° | 12° | 94 mm | 8 | 69% | 44% | 23° | -7° |
| April | 7° | 16° | 113 mm | 9 | 71% | 42% | 27° | -2° |
| May | 12° | 20° | 136 mm | 10 | 79% | 32% | 30° | 3° |
| June | 16° | 23° | 145 mm | 11 | 87% | 26% | 33° | 8° |
| July | 20° | 26° | 142 mm | 12 | 90% | 25% | 37° | 9° |
| August | 22° | 28° | 118 mm | 9 | 89% | 37% | 38° | 13° |
| September | 18° | 26° | 172 mm | 10 | 84% | 29% | 34° | 9° |
| October | 12° | 21° | 186 mm | 9 | 74% | 40% | 32° | 2° |
| November | 6° | 16° | 73 mm | 7 | 70% | 57% | 25° | -3° |
| December | 2° | 11° | 47 mm | 5 | 65% | 62% | 26° | -6° |
Station: ONAHAMA, 11 km from the city. Temperature normal baseline: 1991–2020, calculated from available NOAA GHCN-Daily observations. Available station history: 1970–2026; record values refer to this station and period, not the entire city’s history. Precipitation includes rain and the water equivalent of frozen precipitation; snowfall depth is shown separately when available. Sources and methods
From ERA5 reanalysis. Sunshine is estimated from cloud cover.
Iwaki climate questions
How much rain does Iwaki get?
Iwaki gets 1323 mm of precipitation in an average year, over about 100 rainy days.
What is the wettest month in Iwaki?
October is the wettest month in Iwaki, with 186 mm. February is the driest, with 47 mm.
How many rainy days does Iwaki have a year?
Iwaki has about 100 days with measurable rain in an average year. July has the most, about 12.
What is the hottest month in Iwaki?
August is the warmest month in Iwaki, with an average high of 28°C.
What is the coldest month in Iwaki?
January is the coldest month in Iwaki, with an average low of -1°C.
What is the record high temperature in Iwaki?
Within the available 1970–2026 station history, the record high at the Iwaki station is 38°C, set on August 3, 1994. The record low is -8°C, on January 30, 1985.
What is the sunniest month in Iwaki?
December is the sunniest month in Iwaki, with estimated sunshine of 62% of daylight hours from ERA5 cloud cover. July is the cloudiest.
When is the first frost in Iwaki?
The first fall freeze in Iwaki typically comes around December 5. The last spring freeze is around March 27.
What is the best time to visit Iwaki?
The most comfortable time to visit is typically May to July and September, when daytime highs sit near 24°C.