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Shūnan, Yamaguchi Weather by Month and Climate Averages
Monthly normals · Rain · Snow
Sunshine · Freeze dates · Records · Best time to visit
What is the weather like in Shūnan, Yamaguchi?
Shūnan, Yamaguchi gets 1734 mm of precipitation a year over about 109 rainy days. August is the warmest month (average high 33°C) and January the coldest (average low 0°C).
Humid subtropical climate
Shūnan, Yamaguchi has hot summers and chilly winters. Daytime highs range from about 10°C in January to 33°C in August. July is usually the wettest month. The most comfortable time to visit is typically April to May and October to November, when daytime highs sit near 22°C.
| Season | Months | Avg low | Avg high |
|---|---|---|---|
| Winter | Dec–Feb | 1° | 11° |
| Spring | Mar–May | 8° | 20° |
| Summer | Jun–Aug | 22° | 31° |
| Autumn | Sep–Nov | 13° | 23° |
How much rain does Shūnan get?
Shūnan gets 1734 mm of precipitation in an average year, spread over about 109 days with measurable rain. That is fewer rainy days than 54% of Japan.
July is the wettest month, with 289 mm. December is the driest, with 66 mm. June has the most rainy days, about 11.
The longest dry spell in the last five years lasted 27 days, to November 5, 2023.
From October 2025 to September 2026 Shūnan got 2743 mm of rain, against a normal of 1734 mm for those months. September 2026 had the most, with 1490 mm.
Shūnan weather by month
Shūnan weather in January
In January, Shūnan averages a high of 9°C and a low of 0°C. It gets 68 mm of precipitation over about 10 rainy days. Estimated sunshine is 42% of daylight hours, derived from ERA5 cloud cover. The January record high is 18°C (1997) and the record low is -8°C (2004).
Shūnan weather in February
In February, Shūnan averages a high of 11°C and a low of 0°C. It gets 75 mm of precipitation over about 10 rainy days. Estimated sunshine is 42% of daylight hours, derived from ERA5 cloud cover. The February record high is 22°C (1993) and the record low is -9°C (1977).
Shūnan weather in March
In March, Shūnan averages a high of 14°C and a low of 3°C. It gets 127 mm of precipitation over about 10 rainy days. Estimated sunshine is 41% of daylight hours, derived from ERA5 cloud cover. The March record high is 27°C (2025) and the record low is -8°C (1977).
Shūnan weather in April
In April, Shūnan averages a high of 20°C and a low of 8°C. It gets 155 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 29°C (2004) and the record low is -1°C (1985). April is one of the most comfortable months to visit.
Shūnan weather in May
In May, Shūnan averages a high of 25°C and a low of 13°C. It gets 184 mm of precipitation over about 8 rainy days. Estimated sunshine is 36% of daylight hours, derived from ERA5 cloud cover. The May record high is 34°C (2019) and the record low is 3°C (1971). May is one of the most comfortable months to visit.
Shūnan weather in June
In June, Shūnan averages a high of 28°C and a low of 18°C. It gets 267 mm of precipitation over about 11 rainy days. Estimated sunshine is 25% of daylight hours, derived from ERA5 cloud cover. The June record high is 36°C (2025) and the record low is 8°C (1978).
Shūnan weather in July
In July, Shūnan averages a high of 31°C and a low of 23°C. It gets 289 mm of precipitation over about 11 rainy days. Estimated sunshine is 27% of daylight hours, derived from ERA5 cloud cover. The July record high is 39°C (2018) and the record low is 15°C (1982).
Shūnan weather in August
In August, Shūnan averages a high of 33°C and a low of 23°C. It gets 190 mm of precipitation over about 9 rainy days. Estimated sunshine is 40% of daylight hours, derived from ERA5 cloud cover. The August record high is 39°C (2026) and the record low is 16°C (1971).
Shūnan weather in September
In September, Shūnan averages a high of 29°C and a low of 19°C. It gets 150 mm of precipitation over about 9 rainy days. Estimated sunshine is 39% of daylight hours, derived from ERA5 cloud cover. The September record high is 37°C (2025) and the record low is 7°C (1987).
Shūnan weather in October
In October, Shūnan averages a high of 23°C and a low of 13°C. It gets 86 mm of precipitation over about 6 rainy days. Estimated sunshine is 53% of daylight hours, derived from ERA5 cloud cover. The October record high is 32°C (2021) and the record low is 1°C (1986). October is one of the most comfortable months to visit.
Shūnan weather in November
In November, Shūnan averages a high of 18°C and a low of 7°C. It gets 76 mm of precipitation over about 8 rainy days. Estimated sunshine is 54% of daylight hours, derived from ERA5 cloud cover. The November record high is 28°C (2023) and the record low is -2°C (1976). November is one of the most comfortable months to visit.
Shūnan weather in December
In December, Shūnan averages a high of 12°C and a low of 2°C. It gets 66 mm of precipitation over about 10 rainy days. Estimated sunshine is 44% of daylight hours, derived from ERA5 cloud cover. The December record high is 23°C (2018) and the record low is -6°C (1980).
Sunshine, humidity and wind in Shūnan
November is the sunniest month in Shūnan, with estimated sunshine of 54% of daylight hours from ERA5 cloud cover. June is the cloudiest, at 25%. The annual cloud-cover estimate is 40% of daylight hours; it is not a measurement of sunshine duration. Shūnan is sunnier than 65% of Japan.
Humidity peaks in July at 85% and is lowest in December at 66%.
Shūnan has about 31 days a year above 32°C. Shūnan is hotter than 81% of Japan.
First and last freeze in Shūnan
The first fall freeze in Shūnan typically comes around December 6, and the last spring freeze around March 25. That leaves a frost-free growing season of about 256 days.
Shūnan weather records
These records cover YAMAGUCHI during 1970–2026. Earlier records or other stations in the city may differ.
The hottest temperature on record at the Shūnan station is 39°C, on August 3, 2026. The coldest is -9°C, on February 18, 1977.
The wettest day in the available station history brought 297 mm of precipitation, on July 11, 1972.
42 all-time records have been set at the station since 1970.
The best time to visit Shūnan
The most comfortable time to visit is typically April to May and October to November, when daytime highs sit near 22°C.
Winter (December–February) is chilly, with average highs around 11°C and lows near 1°C.
Spring (March–May) is mild, with average highs around 20°C and lows near 8°C.
Summer (June–August) is hot, with average highs around 30°C and lows near 21°C. It can feel humid.
Autumn (September–November) is warm, with average highs around 23°C and lows near 13°C.
Monthly climate
| Month | Average low | Average high | Precip | Rain days | Humidity | Estimated sunshine | Record high | Record low |
|---|---|---|---|---|---|---|---|---|
| January | 0° | 9° | 68 mm | 10 | 67% | 42% | 18° | -8° |
| February | 0° | 11° | 75 mm | 10 | 68% | 42% | 22° | -9° |
| March | 3° | 14° | 127 mm | 10 | 71% | 41% | 27° | -8° |
| April | 8° | 20° | 155 mm | 9 | 70% | 42% | 29° | -1° |
| May | 13° | 25° | 184 mm | 8 | 75% | 36% | 34° | 3° |
| June | 18° | 28° | 267 mm | 11 | 83% | 25% | 36° | 8° |
| July | 23° | 31° | 289 mm | 11 | 85% | 27% | 39° | 15° |
| August | 23° | 33° | 190 mm | 9 | 82% | 40% | 39° | 16° |
| September | 19° | 29° | 150 mm | 9 | 78% | 39% | 37° | 7° |
| October | 13° | 23° | 86 mm | 6 | 69% | 53% | 32° | 1° |
| November | 7° | 18° | 76 mm | 8 | 68% | 54% | 28° | -2° |
| December | 2° | 12° | 66 mm | 10 | 66% | 44% | 23° | -6° |
Station: YAMAGUCHI, 36 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.
Shūnan climate questions
How much rain does Shūnan get?
Shūnan gets 1734 mm of precipitation in an average year, over about 109 rainy days.
What is the wettest month in Shūnan?
July is the wettest month in Shūnan, with 289 mm. December is the driest, with 66 mm.
How many rainy days does Shūnan have a year?
Shūnan has about 109 days with measurable rain in an average year. June has the most, about 11.
What is the hottest month in Shūnan?
August is the warmest month in Shūnan, with an average high of 33°C.
What is the coldest month in Shūnan?
January is the coldest month in Shūnan, with an average low of 0°C.
What is the record high temperature in Shūnan?
Within the available 1970–2026 station history, the record high at the Shūnan station is 39°C, set on August 3, 2026. The record low is -9°C, on February 18, 1977.
What is the sunniest month in Shūnan?
November is the sunniest month in Shūnan, with estimated sunshine of 54% of daylight hours from ERA5 cloud cover. June is the cloudiest.
When is the first frost in Shūnan?
The first fall freeze in Shūnan typically comes around December 6. The last spring freeze is around March 25.
What is the best time to visit Shūnan?
The most comfortable time to visit is typically April to May and October to November, when daytime highs sit near 22°C.