January Weather in Sumner, United States

Last updated: June 24, 2025

In Sumner, United States, the average temperature in January hovers around 1°C (33°F). Expect wide variations, with lows plunging to a chilly -20°C (-4°F) and highs reaching a comfortable 20°C (68°F). During this month, you'll encounter approximately 91 mm (3.6 in) of precipitation spread over 9 days, accompanied by a high average humidity of 84%. Plan accordingly for a month that fluctuates between stark cold and mild warmth!

January Temperature in Sumner

In January in Sumner, the average temperature is 1°C (33°F). Maximums can reach 20°C (68°F), and minimums can plummet as low as -20°C (-4°F). Be prepared for a wide range of temperatures if you plan to visit during this time.

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

The chart illustrates January temperature patterns in Sumner, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sumner, January typically has an average temperature of 1°C (33°F), with highs reaching up to 20°C (68°F) and lows dropping to around -20°C (-4°F).

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

January Precipitation in Sumner

In Sumner in January, the precipitation amount is 91 mm (3.6 in) spread over 9 days.

January Precipitation Trends in Sumner

The chart displays monthly precipitation patterns in Sumner, 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 Sumner, January typically receives around 91 mm (3.6 inches) of precipitation spread over approximately 9 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 Sumner

In Sumner in January humidity is 84%. With an average temperature of 1°C (33°F), this humidity feels like an icy blanket, making travel uncomfortable and breathless as the frigid air clings to your skin and dampens your clothes.

January Average Humidity in Sumner

This chart illustrates the average monthly humidity levels in Sumner, 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 Sumner is approximately 84%, 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 Sumner

In Sumner 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 Sumner, you can check the information here.

Maximum UV Index Levels in Sumner for January

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

Data source: Sumner 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 Sumner Compares to Other Months

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

This table compares monthly weather conditions in Sumner, 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)	91 mm (3.6 inches)	84%	moderate
February Weather	2°C (37°F)	107 mm (4.2 inches)	82%	moderate
March Weather	8°C (47°F)	133 mm (5.2 inches)	84%	high
April Weather	13°C (56°F)	120 mm (4.7 inches)	83%	very high
May Weather	20°C (68°F)	133 mm (5.3 inches)	80%	very high
June Weather	25°C (77°F)	112 mm (4.4 inches)	83%	extreme
July Weather	26°C (80°F)	97 mm (3.8 inches)	82%	very high
August Weather	25°C (77°F)	92 mm (3.6 inches)	82%	very high
September Weather	22°C (73°F)	70 mm (2.7 inches)	79%	very high
October Weather	16°C (60°F)	100 mm (3.9 inches)	79%	high
November Weather	7°C (44°F)	102 mm (4.0 inches)	88%	moderate
December Weather	4°C (39°F)	95 mm (3.7 inches)	87%	moderate