January Weather in Joetsu, Japan

Last updated: August 23, 2025

In January, the average temperature in Joetsu, Japan hovers around 3°C (38°F). Expect chilly days with a minimum of -5°C (24°F) and a mild maximum of 14°C (57°F). With an average precipitation of 233 mm (9.2 in) spread over 22 days, this month is likely to be quite wet, and a high average humidity of 88% adds to the overall dampness. Be sure to pack accordingly!

January Temperature in Joetsu

In January in Joetsu, the average temperature is 3°C (38°F). Maximum temperatures can reach 14°C (57°F), while minimums can drop to as low as -5°C (24°F). Travelers should be prepared for chilly conditions and varying temperatures during this time.

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

The chart illustrates January temperature patterns in Joetsu, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Joetsu, January typically has an average temperature of 3°C (38°F), with highs reaching up to 14°C (57°F) and lows dropping to around -5°C (24°F).

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

January Precipitation in Joetsu

In Joetsu in January, the total precipitation amount is 233 mm (9.2 in), distributed over a period of 22 days.

January Precipitation Trends in Joetsu

The chart displays monthly precipitation patterns in Joetsu, 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 Joetsu, January typically receives around 233 mm (9.2 inches) of precipitation spread over approximately 22 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 Joetsu

In Joetsu in January, humidity is 88%. With an average temperature of 3°C (38°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities less enjoyable and requiring extra layers to stay comfortable while traveling.

January Average Humidity in Joetsu

This chart illustrates the average monthly humidity levels in Joetsu, 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 Joetsu 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 Joetsu

In Joetsu 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 Joetsu, you can check the information here.

Maximum UV Index Levels in Joetsu for January

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

Data source: Joetsu 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 Joetsu Compares to Other Months

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

This table compares monthly weather conditions in Joetsu, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	3°C (38°F)	233 mm (9.2 inches)	88%	moderate
February Weather	4°C (39°F)	181 mm (7.1 inches)	86%	moderate
March Weather	8°C (46°F)	128 mm (5.0 inches)	81%	very high
April Weather	12°C (53°F)	121 mm (4.7 inches)	78%	very high
May Weather	17°C (64°F)	105 mm (4.1 inches)	81%	very high
June Weather	21°C (70°F)	105 mm (4.1 inches)	88%	extreme
July Weather	26°C (79°F)	290 mm (11.4 inches)	92%	extreme
August Weather	27°C (82°F)	157 mm (6.2 inches)	92%	extreme
September Weather	23°C (74°F)	171 mm (6.7 inches)	89%	very high
October Weather	18°C (64°F)	190 mm (7.5 inches)	87%	high
November Weather	12°C (53°F)	170 mm (6.7 inches)	85%	moderate
December Weather	6°C (43°F)	273 mm (10.7 inches)	86%	moderate