January Weather in Boise, United States

Last updated: June 24, 2025

In January, the average temperature in Boise, United States hovers around 1°C (33°F), showcasing the chilly embrace of winter. Minimum temperatures can plunge to a frigid -22°C (-7°F), while maximums may reach a mild 13°C (56°F). Expect 49 mm (1.9 in) of precipitation over 10 days, contributing to the region's average humidity of 88%. Prepare for a cozy yet brisk experience!

January Temperature in Boise

In January in Boise, the average temperature is 1°C (33°F). The maximum can reach 13°C (56°F), and the minimum can be as low as -22°C (-7°F). Travelers should be prepared for chilly conditions and pack layers for both warm and cold weather.

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

The chart illustrates January temperature patterns in Boise, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Boise, January typically has an average temperature of 1°C (33°F), with highs reaching up to 13°C (56°F) and lows dropping to around -22°C (-7°F).

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

January Precipitation in Boise

In Boise in January, the total precipitation amount is 49 mm (1.9 in) over the course of 10 days.

January Precipitation Trends in Boise

The chart displays monthly precipitation patterns in Boise, 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 Boise, January typically receives around 49 mm (1.9 inches) of precipitation spread over approximately 10 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 Boise

In Boise in January humidity is 88%. With an average temperature of 1°C (33°F), this humidity feels like a damp chill wrapping around you, making it difficult to stay warm while traveling, as each breath carries a heavy, cold moisture that clings to your skin.

January Average Humidity in Boise

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

In Boise 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 Boise, you can check the information here.

Maximum UV Index Levels in Boise for January

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

Data source: Boise 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 Boise Compares to Other Months

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

This table compares monthly weather conditions in Boise, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	1°C (33°F)	49 mm (1.9 inches)	88%	moderate
February Weather	2°C (36°F)	50 mm (2.0 inches)	89%	moderate
March Weather	8°C (46°F)	38 mm (1.5 inches)	85%	high
April Weather	11°C (52°F)	36 mm (1.4 inches)	79%	very high
May Weather	16°C (61°F)	39 mm (1.5 inches)	71%	very high
June Weather	21°C (71°F)	21 mm (0.8 inches)	71%	extreme
July Weather	27°C (81°F)	1 mm (0.0 inches)	66%	extreme
August Weather	26°C (78°F)	8 mm (0.3 inches)	50%	very high
September Weather	20°C (68°F)	10 mm (0.4 inches)	48%	very high
October Weather	11°C (53°F)	22 mm (0.9 inches)	65%	high
November Weather	6°C (43°F)	32 mm (1.3 inches)	84%	moderate
December Weather	1°C (34°F)	40 mm (1.6 inches)	87%	low