December Weather in Isumi, Japan

Last updated: August 23, 2025

In December, the average temperature in Isumi, Japan is a comfortable 11°C (53°F), perfect for exploring. Expect a chilly minimum of 3°C (37°F) and a pleasant maximum of 21°C (71°F). Be prepared for 114 mm (4.5 in) of precipitation spread over about 12 days, contributing to an average humidity of 72%. Ideal for cozy adventures, so pack accordingly!

December Temperature in Isumi

In December in Isumi, the average temperature is 11°C (53°F). Maximum temperatures can reach 21°C (71°F), while minimums can drop to as low as 3°C (37°F). This climate makes Isumi a comfortable destination for those looking to explore without extreme heat or cold.

December Weather in Isumi: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Isumi, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Isumi, December typically has an average temperature of 11°C (53°F), with highs reaching up to 21°C (71°F) and lows dropping to around 3°C (37°F).

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

December Precipitation in Isumi

In Isumi in December, the precipitation amount is 114 mm (4.5 in) spread over 12 days.

December Precipitation Trends in Isumi

The chart displays monthly precipitation patterns in Isumi, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Isumi, December typically receives around 114 mm (4.5 inches) of precipitation spread over approximately 12 days.

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

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Millimeters (mm) Inches (in)

December Humidity in Isumi

In Isumi in December, humidity is 72%. With an average temperature of 11°C (53°F), this humidity feels like a damp chill that clings to your skin, making outdoor activities slightly uncomfortable and the air heavy, which can dampen the enjoyment of sightseeing and exploring.

December Average Humidity in Isumi

This chart illustrates the average monthly humidity levels in Isumi, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Isumi is approximately 72%, offering insight into how humid the weather typically is during this month.

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

December UV Index in Isumi

In Isumi in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Isumi for better planning.

Maximum UV Index Levels in Isumi for December

The chart shows the monthly maximum UV Index (UVI) for Isumi in December, 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 December, the maximum UV index in Isumi typically reaches 4, which falls under the moderate exposure category.

Data source: Isumi December 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 December Weather in Isumi Compares to Other Months

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

This table compares monthly weather conditions in Isumi, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	9°C (48°F)	77 mm (3.0 inches)	70%	moderate
February Weather	9°C (48°F)	68 mm (2.7 inches)	69%	moderate
March Weather	12°C (54°F)	180 mm (7.1 inches)	68%	very high
April Weather	15°C (59°F)	117 mm (4.6 inches)	73%	very high
May Weather	19°C (67°F)	140 mm (5.5 inches)	81%	extreme
June Weather	22°C (72°F)	206 mm (8.1 inches)	88%	extreme
July Weather	25°C (78°F)	206 mm (8.1 inches)	94%	extreme
August Weather	27°C (81°F)	113 mm (4.5 inches)	87%	extreme
September Weather	25°C (77°F)	214 mm (8.4 inches)	83%	very high
October Weather	21°C (69°F)	292 mm (11.5 inches)	78%	high
November Weather	16°C (62°F)	142 mm (5.6 inches)	74%	moderate
December Weather	11°C (53°F)	114 mm (4.5 inches)	72%	moderate