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Monthly climate in Seto, Japan

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Seto features a humid subtropical climate (Cfa). Temperatures typically range between 5 °C (41 °F) and 29 °C (85 °F) through the year, but rarely can drop to -5 °C (23 °F) or can rise to as high as 39 °C (103 °F). The average annual precipitation amounts to about 1627 mm (64.1 inches) and receives 123 rainy days on the 1 mm (0.04 inches) threshold annually. Seto enjoys an average of 3012 hours of sunshine throughout the year, and daylight varies from 9 hours 49 minutes to 14 hours 28 minutes per day.

Monthly average temperatures in Seto, Japan

The warmest months in Seto are July, August and September, with daily mean temperatures ranging from 25 to 29 °C (77 - 85 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 5 to 7 °C (41 - 45 °F) throughout the day. On average each year, Seto experiences 122 days above 25 °C (77.0 °F) and 33 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Seto. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum17°C
(64°F)		21°C
(71°F)		25°C
(77°F)		28°C
(83°F)		32°C
(90°F)		34°C
(93°F)		38°C
(100°F)		39°C
(103°F)		38°C
(101°F)		32°C
(90°F)		25°C
(76°F)		21°C
(70°F)
Mean maximum15°C
(59°F)		17°C
(63°F)		22°C
(72°F)		27°C
(80°F)		30°C
(87°F)		31°C
(89°F)		35°C
(95°F)		37°C
(100°F)		35°C
(95°F)		30°C
(86°F)		23°C
(74°F)		18°C
(64°F)
Average high10°C
(50°F)		11°C
(52°F)		16°C
(61°F)		20°C
(68°F)		25°C
(77°F)		28°C
(82°F)		31°C
(88°F)		33°C
(92°F)		29°C
(84°F)		23°C
(75°F)		18°C
(65°F)		12°C
(54°F)
Daily mean5°C
(41°F)		6°C
(43°F)		10°C
(51°F)		15°C
(59°F)		20°C
(68°F)		23°C
(74°F)		27°C
(81°F)		29°C
(85°F)		25°C
(77°F)		19°C
(66°F)		13°C
(55°F)		7°C
(45°F)
Average low0°C
(33°F)		1°C
(34°F)		5°C
(41°F)		9°C
(49°F)		14°C
(58°F)		19°C
(66°F)		24°C
(75°F)		25°C
(78°F)		21°C
(70°F)		15°C
(59°F)		7°C
(46°F)		3°C
(37°F)
Mean minimum-4°C
(26°F)		-3°C
(27°F)		-1°C
(31°F)		2°C
(36°F)		6°C
(44°F)		14°C
(57°F)		20°C
(69°F)		21°C
(70°F)		15°C
(59°F)		8°C
(47°F)		1°C
(35°F)		-2°C
(28°F)
Minimum-5°C
(23°F)		-4°C
(24°F)		-2°C
(29°F)		-1°C
(30°F)		5°C
(41°F)		12°C
(53°F)		20°C
(67°F)		19°C
(67°F)		12°C
(53°F)		7°C
(44°F)		0°C
(32°F)		-3°C
(28°F)

Compare climate in Seto with other places

Compare temperature, precipitation, sunshine, UV index in Seto, Japan with other places around the world.

Monthly average precipitation in Seto, Japan

Seto usually has the most precipitation in May, July and October, with an average of 13 rainy days and 226 mm (8.9 inches) of precipitation per month. The driest months in Seto are January, February and December. On average, 49 mm (1.9 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Seto. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)43 (1.7)52 (2.0)126 (5.0)142 (5.6)173 (6.8)148 (5.8)295 (11.6)169 (6.7)165 (6.5)210 (8.2)54 (2.1)51 (2.0)
Average precipitation days (≥ 1 mm)559910131914161265

Monthly sunshine hours in Seto, Japan

The sunniest months in Seto are April, May and August, when the sun shines an average of 9 hours 24 minutes a day. Least sunny months in Seto: January, February and December receive an average of 7 hours 0 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Seto. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours184230264276290269255299244234239222
Mean daily daylight hours10h 3m10h 53m11h 58m13h 4m14h 0m14h 28m14h 14m13h 25m12h 22m11h 16m10h 18m9h 49m

Solar UV radiation in Seto, Japan

Seto experiences the highest level of ultraviolet (UV) radiation in May, July and August, when the maximum UV index can reach values of 11 - 11, which corresponds to the Extreme category of sun exposure. January, November and December are in the Moderate exposure category. In these months, the maximum values of the UV index do not exceed 5. For more detailed information, check out our hourly Seto UV Index data.

Average daily maximum UV levels by month for Seto. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)468101111111110753