January Weather in Koga, Japan

Last updated: August 23, 2025

In January, the average temperature in Koga, Japan hovers around 4°C (39°F), with minimums dipping to -10°C (14°F) and reaching a maximum of 16°C (62°F). Expect a precipitation level of approximately 38 mm (1.5 in) over about 4 days, accompanied by a high average humidity of 88%.

January Temperature in Koga

In January in Koga, the average temperature is 4°C (39°F), with maximums reaching up to 16°C (62°F) and minimums plummeting as low as -10°C (14°F). Travelers should be prepared for a wide range of temperatures and pack accordingly for both chilly and mild conditions.

January Weather in Koga: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Koga, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Koga, January typically has an average temperature of 4°C (39°F), with highs reaching up to 16°C (62°F) and lows dropping to around -10°C (14°F).

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

January Precipitation in Koga

In Koga in January, the total precipitation amount is 38 mm (1.5 in) spread over the course of 4 days.

January Precipitation Trends in Koga

The chart displays monthly precipitation patterns in Koga, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Koga, January typically receives around 38 mm (1.5 inches) of precipitation spread over approximately 4 days.

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

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Millimeters (mm) Inches (in)

January Humidity in Koga

In Koga in January, humidity is 88%. With an average temperature of 4°C (39°F), this humidity feels like a damp chill that seeps into your bones, making travel uncomfortable and necessitating extra layers to stay warm.

January Average Humidity in Koga

This chart illustrates the average monthly humidity levels in Koga, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Koga is approximately 88%, offering insight into how humid the weather typically is during this month.

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

January UV Index in Koga

In Koga in January, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Koga, you can check the information here.

Maximum UV Index Levels in Koga for January

The chart shows the monthly maximum UV Index (UVI) for Koga in January, 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 January, the maximum UV index in Koga typically reaches 3, which falls under the moderate exposure category.

Data source: Koga January 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 January Weather in Koga Compares to Other Months

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

This table compares monthly weather conditions in Koga, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	4°C (39°F)	38 mm (1.5 inches)	88%	moderate
February Weather	5°C (41°F)	41 mm (1.6 inches)	86%	moderate
March Weather	9°C (49°F)	131 mm (5.2 inches)	81%	high
April Weather	14°C (57°F)	129 mm (5.1 inches)	78%	very high
May Weather	19°C (66°F)	137 mm (5.4 inches)	81%	very high
June Weather	22°C (72°F)	160 mm (6.3 inches)	88%	extreme
July Weather	26°C (78°F)	258 mm (10.2 inches)	92%	extreme
August Weather	27°C (82°F)	156 mm (6.1 inches)	92%	very high
September Weather	23°C (74°F)	195 mm (7.7 inches)	89%	very high
October Weather	18°C (64°F)	258 mm (10.1 inches)	87%	high
November Weather	12°C (53°F)	67 mm (2.6 inches)	85%	moderate
December Weather	6°C (43°F)	50 mm (2.0 inches)	86%	moderate