May Weather in Koshu, Japan

Last updated: August 23, 2025

In May, the average temperature in Koshu, Japan rests at a pleasant 14°C (58°F). However, temperatures can swing from a chilly 0°C (33°F) to a warm 28°C (82°F). Expect some rain, with a total precipitation of 148 mm (5.8 in) spread over 15 days. The air is notably humid, with average humidity levels around 81%.

May Temperature in Koshu

In May in Koshu, the average temperature is 14°C (58°F), with maximums reaching 28°C (82°F) and minimums dropping as low as 0°C (33°F). It's advisable to pack both light clothing for the warmer days and warmer layers for the cooler nights as you explore this destination.

May Weather in Koshu: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Koshu, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Koshu, May typically has an average temperature of 14°C (58°F), with highs reaching up to 28°C (82°F) and lows dropping to around 0°C (33°F).

Data source: Temperature data for Koshu generated using information from the Copernicus Climate Change Service.

May Precipitation in Koshu

In Koshu, in May, the precipitation amount is 148 mm (5.8 in) over a span of 15 days.

May Precipitation Trends in Koshu

The chart displays monthly precipitation patterns in Koshu, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In Koshu, May typically receives around 148 mm (5.8 inches) of precipitation spread over approximately 15 days.

Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

May Humidity in Koshu

In Koshu in May, humidity is 81%. With an average temperature of 14°C (58°F), this humidity feels like a warm blanket wrapping around you, making outdoor adventures sticky and challenging, while also providing a lush, vibrant atmosphere perfect for exploring.

May Average Humidity in Koshu

This chart illustrates the average monthly humidity levels in Koshu, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in Koshu is approximately 81%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Koshu

In Koshu in May, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Koshu.

Maximum UV Index Levels in Koshu for May

The chart shows the monthly maximum UV Index (UVI) for Koshu in May, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In May, the maximum UV index in Koshu typically reaches 11, which falls under the extreme exposure category.

Data source: Koshu May UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How May Weather in Koshu Compares to Other Months

Weather in Koshu varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in Koshu, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Koshu, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-1°C (31°F)	48 mm (1.9 inches)	76%	moderate
February Weather	0°C (33°F)	58 mm (2.3 inches)	74%	high
March Weather	5°C (41°F)	144 mm (5.7 inches)	70%	very high
April Weather	9°C (48°F)	138 mm (5.4 inches)	74%	very high
May Weather	14°C (58°F)	148 mm (5.8 inches)	81%	extreme
June Weather	17°C (63°F)	179 mm (7.1 inches)	88%	extreme
July Weather	21°C (70°F)	320 mm (12.6 inches)	93%	extreme
August Weather	23°C (73°F)	190 mm (7.5 inches)	90%	extreme
September Weather	18°C (65°F)	208 mm (8.2 inches)	86%	very high
October Weather	13°C (55°F)	324 mm (12.8 inches)	83%	high
November Weather	7°C (45°F)	56 mm (2.2 inches)	80%	moderate
December Weather	2°C (36°F)	52 mm (2.1 inches)	78%	moderate