December Weather in Ketchum, United States

Last updated: June 24, 2025

In Ketchum, United States during December, the average temperature hovers around -9°C (16°F), with lows plunging to -25°C (-12°F) and highs reaching a mild 8°C (46°F). Expect 49 mm (1.9 in) of precipitation spread over 10 days, contributing to an average humidity level of 87%. Engage your senses and prepare for a winter wonderland!

December Temperature in Ketchum

In December in Ketchum, the average temperature is -9°C (16°F), with maximums reaching 8°C (46°F) and minimums plunging as low as -25°C (-12°F). Travel prepared for cold weather and be mindful of the wide temperature fluctuations during this time.

December Weather in Ketchum: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Ketchum, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Ketchum, December typically has an average temperature of -9°C (16°F), with highs reaching up to 8°C (46°F) and lows dropping to around -25°C (-12°F).

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

December Precipitation in Ketchum

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

December Precipitation Trends in Ketchum

The chart displays monthly precipitation patterns in Ketchum, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Ketchum, December typically receives around 49 mm (1.9 inches) of precipitation spread over approximately 10 days.

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

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Millimeters (mm) Inches (in)

December Humidity in Ketchum

In Ketchum in December humidity is 87%. With an average temperature of -9°C (16°F), this humidity feels like a heavy blanket of moisture that clings to your skin, making it uncomfortable for traveling and causing your breath to mist in the cold air while navigating the wintry landscape.

December Average Humidity in Ketchum

This chart illustrates the average monthly humidity levels in Ketchum, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Ketchum is approximately 87%, offering insight into how humid the weather typically is during this month.

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

December UV Index in Ketchum

In Ketchum in December, 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 Ketchum, you can check the information here.

Maximum UV Index Levels in Ketchum for December

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

Data source: Ketchum December 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 December Weather in Ketchum Compares to Other Months

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

This table compares monthly weather conditions in Ketchum, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-8°C (17°F)	56 mm (2.2 inches)	91%	moderate
February Weather	-8°C (18°F)	86 mm (3.4 inches)	92%	moderate
March Weather	-3°C (26°F)	60 mm (2.4 inches)	85%	very high
April Weather	0°C (31°F)	52 mm (2.0 inches)	76%	very high
May Weather	4°C (40°F)	61 mm (2.4 inches)	66%	extreme
June Weather	11°C (52°F)	46 mm (1.8 inches)	62%	extreme
July Weather	16°C (62°F)	15 mm (0.6 inches)	53%	extreme
August Weather	15°C (60°F)	33 mm (1.3 inches)	42%	very high
September Weather	10°C (51°F)	30 mm (1.2 inches)	46%	very high
October Weather	2°C (35°F)	42 mm (1.6 inches)	64%	high
November Weather	-4°C (26°F)	46 mm (1.8 inches)	83%	moderate
December Weather	-9°C (16°F)	49 mm (1.9 inches)	87%	moderate