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Iwata, Shizuoka Weather by Month and Climate Averages
Monthly normals · Rain · Snow
Sunshine · Freeze dates · Records · Best time to visit
What is the weather like in Iwata, Shizuoka?
Iwata, Shizuoka gets 1582 mm of precipitation a year over about 91 rainy days. August is the warmest month (average high 32°C) and January the coldest (average low 2°C).
Humid subtropical climate
Iwata, Shizuoka has hot summers and chilly winters. Daytime highs range from about 10°C in January to 32°C in August. September is usually the wettest month. The most comfortable time to visit is typically April to June and October to November, when daytime highs sit near 22°C.
| Season | Months | Avg low | Avg high |
|---|---|---|---|
| Winter | Dec–Feb | 3° | 12° |
| Spring | Mar–May | 10° | 19° |
| Summer | Jun–Aug | 22° | 29° |
| Autumn | Sep–Nov | 16° | 23° |
How much rain does Iwata get?
Iwata gets 1582 mm of precipitation in an average year, spread over about 91 days with measurable rain. That is fewer rainy days than 91% of Japan.
September is the wettest month, with 203 mm. December is the driest, with 51 mm. June has the most rainy days, about 11.
The longest dry spell in the last five years lasted 21 days, to January 12, 2023.
From October 2025 to September 2026 Iwata got 3464 mm of rain, against a normal of 1582 mm for those months. September 2026 had the most, with 1757 mm.
Iwata weather by month
Iwata weather in January
In January, Iwata averages a high of 11°C and a low of 2°C. It gets 52 mm of precipitation over about 5 rainy days. Estimated sunshine is 64% of daylight hours, derived from ERA5 cloud cover. The January record high is 19°C (1972) and the record low is -4°C (1997).
Iwata weather in February
In February, Iwata averages a high of 12°C and a low of 2°C. It gets 71 mm of precipitation over about 6 rainy days. Estimated sunshine is 57% of daylight hours, derived from ERA5 cloud cover. The February record high is 23°C (2024) and the record low is -6°C (1981).
Iwata weather in March
In March, Iwata averages a high of 15°C and a low of 5°C. It gets 131 mm of precipitation over about 8 rainy days. Estimated sunshine is 48% of daylight hours, derived from ERA5 cloud cover. The March record high is 26°C (2023) and the record low is -3°C (1977).
Iwata weather in April
In April, Iwata averages a high of 20°C and a low of 10°C. It gets 153 mm of precipitation over about 8 rainy days. Estimated sunshine is 40% of daylight hours, derived from ERA5 cloud cover. The April record high is 28°C (2005) and the record low is 1°C (1972). April is one of the most comfortable months to visit.
Iwata weather in May
In May, Iwata averages a high of 24°C and a low of 14°C. It gets 159 mm of precipitation over about 8 rainy days. Estimated sunshine is 32% of daylight hours, derived from ERA5 cloud cover. The May record high is 32°C (2015) and the record low is 7°C (1972). May is one of the most comfortable months to visit.
Iwata weather in June
In June, Iwata averages a high of 27°C and a low of 19°C. It gets 195 mm of precipitation over about 11 rainy days. Estimated sunshine is 23% of daylight hours, derived from ERA5 cloud cover. The June record high is 37°C (2011) and the record low is 12°C (1978). June is one of the most comfortable months to visit.
Iwata weather in July
In July, Iwata averages a high of 30°C and a low of 23°C. It gets 185 mm of precipitation over about 10 rainy days. Estimated sunshine is 29% of daylight hours, derived from ERA5 cloud cover. The July record high is 40°C (2026) and the record low is 16°C (1976).
Iwata weather in August
In August, Iwata averages a high of 32°C and a low of 24°C. It gets 108 mm of precipitation over about 7 rainy days. Estimated sunshine is 36% of daylight hours, derived from ERA5 cloud cover. The August record high is 41°C (2020) and the record low is 18°C (1986).
Iwata weather in September
In September, Iwata averages a high of 29°C and a low of 21°C. It gets 203 mm of precipitation over about 10 rainy days. Estimated sunshine is 35% of daylight hours, derived from ERA5 cloud cover. The September record high is 37°C (2003) and the record low is 13°C (1980).
Iwata weather in October
In October, Iwata averages a high of 24°C and a low of 16°C. It gets 180 mm of precipitation over about 8 rainy days. Estimated sunshine is 46% of daylight hours, derived from ERA5 cloud cover. The October record high is 32°C (2013) and the record low is 7°C (1986). October is one of the most comfortable months to visit.
Iwata weather in November
In November, Iwata averages a high of 18°C and a low of 9°C. It gets 95 mm of precipitation over about 6 rainy days. Estimated sunshine is 60% of daylight hours, derived from ERA5 cloud cover. The November record high is 28°C (2000) and the record low is 1°C (1988). November is one of the most comfortable months to visit.
Iwata weather in December
In December, Iwata averages a high of 13°C and a low of 4°C. It gets 51 mm of precipitation over about 4 rainy days. Estimated sunshine is 71% of daylight hours, derived from ERA5 cloud cover. The December record high is 23°C (2015) and the record low is -2°C (1973).
Sunshine, humidity and wind in Iwata
December is the sunniest month in Iwata, with estimated sunshine of 71% of daylight hours from ERA5 cloud cover. June is the cloudiest, at 23%. The annual cloud-cover estimate is 45% of daylight hours; it is not a measurement of sunshine duration. Iwata is sunnier than 99% of Japan.
Humidity peaks in September at 78% and is lowest in February at 57%.
Iwata has about 19 days a year above 32°C. Iwata is cooler than 52% of Japan.
First and last freeze in Iwata
The first fall freeze in Iwata typically comes around December 20, and the last spring freeze around February 25. That leaves a frost-free growing season of about 298 days.
Iwata weather records
These records cover HAMAMATSU during 1970–2026. Earlier records or other stations in the city may differ.
The hottest temperature on record at the Iwata station is 41°C, on August 17, 2020. The coldest is -6°C, on February 27, 1981.
The wettest day in the available station history brought 377 mm of precipitation, on August 8, 2026.
50 all-time records have been set at the station since 1970.
The best time to visit Iwata
The most comfortable time to visit is typically April to June and October to November, when daytime highs sit near 22°C.
Winter (December–February) is chilly, with average highs around 12°C and lows near 3°C.
Spring (March–May) is mild, with average highs around 20°C and lows near 10°C.
Summer (June–August) is hot, with average highs around 29°C and lows near 22°C. It can feel humid.
Autumn (September–November) is warm, with average highs around 24°C and lows near 15°C.
Monthly climate
| Month | Average low | Average high | Precip | Rain days | Humidity | Estimated sunshine | Record high | Record low |
|---|---|---|---|---|---|---|---|---|
| January | 2° | 11° | 52 mm | 5 | 58% | 64% | 19° | -4° |
| February | 2° | 12° | 71 mm | 6 | 57% | 57% | 23° | -6° |
| March | 5° | 15° | 131 mm | 8 | 60% | 48% | 26° | -3° |
| April | 10° | 20° | 153 mm | 8 | 63% | 40% | 28° | 1° |
| May | 14° | 24° | 159 mm | 8 | 68% | 32% | 32° | 7° |
| June | 19° | 27° | 195 mm | 11 | 75% | 23% | 37° | 12° |
| July | 23° | 30° | 185 mm | 10 | 76% | 29% | 40° | 16° |
| August | 24° | 32° | 108 mm | 7 | 74% | 36% | 41° | 18° |
| September | 21° | 29° | 203 mm | 10 | 78% | 35% | 37° | 13° |
| October | 16° | 24° | 180 mm | 8 | 71% | 46% | 32° | 7° |
| November | 9° | 18° | 95 mm | 6 | 66% | 60% | 28° | 1° |
| December | 4° | 13° | 51 mm | 4 | 58% | 71% | 23° | -2° |
Station: HAMAMATSU, 12 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.
Iwata climate questions
How much rain does Iwata get?
Iwata gets 1582 mm of precipitation in an average year, over about 91 rainy days.
What is the wettest month in Iwata?
September is the wettest month in Iwata, with 203 mm. December is the driest, with 51 mm.
How many rainy days does Iwata have a year?
Iwata has about 91 days with measurable rain in an average year. June has the most, about 11.
What is the hottest month in Iwata?
August is the warmest month in Iwata, with an average high of 32°C.
What is the coldest month in Iwata?
January is the coldest month in Iwata, with an average low of 2°C.
What is the record high temperature in Iwata?
Within the available 1970–2026 station history, the record high at the Iwata station is 41°C, set on August 17, 2020. The record low is -6°C, on February 27, 1981.
What is the sunniest month in Iwata?
December is the sunniest month in Iwata, with estimated sunshine of 71% of daylight hours from ERA5 cloud cover. June is the cloudiest.
When is the first frost in Iwata?
The first fall freeze in Iwata typically comes around December 20. The last spring freeze is around February 25.
What is the best time to visit Iwata?
The most comfortable time to visit is typically April to June and October to November, when daytime highs sit near 22°C.