December Weather in Koya, Japan

Last updated: August 23, 2025

In Koya, Japan, the average temperature in December hovers around 7°C (44°F). This month can bring a chill with minimum temperatures dipping to -2°C (29°F), while highs can reach a pleasant 21°C (70°F). Expect about 79 mm (3.1 in) of precipitation over 9 days, leading to a high average humidity of 83%. Stay prepared for a mix of cool and wet weather!

December Temperature in Koya

In December in Koya, the average temperature is 7°C (44°F). The maximum can reach 21°C (70°F) and the minimum can be as low as -2°C (29°F). It's advisable to pack layers for your travel, as the weather can vary significantly throughout the day.

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

The chart illustrates December temperature patterns in Koya, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Koya, December typically has an average temperature of 7°C (44°F), with highs reaching up to 21°C (70°F) and lows dropping to around -2°C (29°F).

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

December Precipitation in Koya

In Koya in December, the precipitation amount is 79 mm (3.1 in) spread over 9 days.

December Precipitation Trends in Koya

The chart displays monthly precipitation patterns in Koya, 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 Koya, December typically receives around 79 mm (3.1 inches) of precipitation spread over approximately 9 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 Koya

In Koya in December, humidity is 83%. With an average temperature of 7°C (44°F), this humidity feels like a damp chill that seeps into your bones, making exploring outdoors somewhat uncomfortable and requiring extra layers to stay warm and dry.

December Average Humidity in Koya

This chart illustrates the average monthly humidity levels in Koya, 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 Koya is approximately 83%, 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 Koya

In Koya 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 Koya for better planning.

Maximum UV Index Levels in Koya for December

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

Data source: Koya 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 Koya Compares to Other Months

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

This table compares monthly weather conditions in Koya, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	4°C (40°F)	67 mm (2.6 inches)	82%	moderate
February Weather	5°C (41°F)	83 mm (3.3 inches)	79%	high
March Weather	9°C (49°F)	127 mm (5.0 inches)	74%	very high
April Weather	14°C (57°F)	132 mm (5.2 inches)	76%	extreme
May Weather	19°C (66°F)	169 mm (6.7 inches)	83%	extreme
June Weather	22°C (72°F)	220 mm (8.7 inches)	87%	extreme
July Weather	26°C (79°F)	324 mm (12.7 inches)	93%	extreme
August Weather	28°C (82°F)	203 mm (8.0 inches)	91%	extreme
September Weather	24°C (75°F)	204 mm (8.0 inches)	87%	very high
October Weather	18°C (65°F)	265 mm (10.5 inches)	85%	high
November Weather	12°C (54°F)	62 mm (2.4 inches)	83%	high
December Weather	7°C (44°F)	79 mm (3.1 inches)	83%	moderate