January Weather in Iiyama, Japan

Last updated: August 23, 2025

In January, the average temperature in Iiyama, Japan hovers around -2°C (29°F). During this chilly month, temperatures can dip as low as -15°C (6°F), while peaking at a more moderate 10°C (51°F). Expect significant precipitation, with 144 mm (5.7 in) falling over 21 days, and keep in mind the air is often quite damp, with an average humidity of 88%.

January Temperature in Iiyama

In January in Iiyama, the average temperature is -2°C (29°F). The maximum can reach 10°C (51°F) and the minimum can be as low as -15°C (6°F). Travelers should be prepared for chilly conditions and pack accordingly to fully enjoy the winter charm of Iiyama.

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

The chart illustrates January temperature patterns in Iiyama, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Iiyama, January typically has an average temperature of -2°C (29°F), with highs reaching up to 10°C (51°F) and lows dropping to around -15°C (6°F).

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

January Precipitation in Iiyama

In Iiyama in January, the precipitation amount is 144 mm (5.7 in) over a span of 21 days.

January Precipitation Trends in Iiyama

The chart displays monthly precipitation patterns in Iiyama, 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 Iiyama, January typically receives around 144 mm (5.7 inches) of precipitation spread over approximately 21 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 Iiyama

In Iiyama in January, humidity is 88%. With an average temperature of -2°C (29°F), this humidity feels like a biting chill in the air that penetrates layers of clothing, making outdoor activities challenging and potentially uncomfortable for travelers.

January Average Humidity in Iiyama

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

In Iiyama in January, 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 Iiyama for better planning.

Maximum UV Index Levels in Iiyama for January

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

Data source: Iiyama 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 Iiyama Compares to Other Months

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

This table compares monthly weather conditions in Iiyama, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (29°F)	144 mm (5.7 inches)	88%	moderate
February Weather	-1°C (30°F)	129 mm (5.1 inches)	86%	high
March Weather	4°C (39°F)	133 mm (5.2 inches)	81%	very high
April Weather	9°C (48°F)	141 mm (5.5 inches)	78%	very high
May Weather	15°C (59°F)	160 mm (6.3 inches)	81%	extreme
June Weather	18°C (65°F)	171 mm (6.7 inches)	88%	extreme
July Weather	22°C (73°F)	341 mm (13.4 inches)	92%	extreme
August Weather	24°C (75°F)	198 mm (7.8 inches)	92%	extreme
September Weather	19°C (67°F)	194 mm (7.6 inches)	89%	very high
October Weather	13°C (56°F)	217 mm (8.5 inches)	87%	high
November Weather	7°C (44°F)	94 mm (3.7 inches)	85%	moderate
December Weather	1°C (34°F)	151 mm (6.0 inches)	86%	moderate