January Weather in Castle Rock, United States

Last updated: June 24, 2025

The average temperature in Castle Rock, United States during January is a brisk 5°C (41°F). Expect chilly lows of -9°C (16°F) and mild highs reaching up to 15°C (59°F). This month also brings 190 mm (7.5 in) of precipitation over 17 days, contributing to an average humidity level of 86%. Prepare accordingly for a damp and cool climate!

January Temperature in Castle Rock

In January in Castle Rock, the average temperature is 5°C (41°F). Maximum temperatures can reach up to 15°C (59°F), while minimums can dip as low as -9°C (16°F). Travelers should prepare for a mix of chilly days and mild afternoons, making layer options essential for comfort.

January Weather in Castle Rock: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Castle Rock, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Castle Rock, January typically has an average temperature of 5°C (41°F), with highs reaching up to 15°C (59°F) and lows dropping to around -9°C (16°F).

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

January Precipitation in Castle Rock

In Castle Rock in January, the total precipitation amount is 190 mm (7.5 in) spread over 17 days.

January Precipitation Trends in Castle Rock

The chart displays monthly precipitation patterns in Castle Rock, 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 Castle Rock, January typically receives around 190 mm (7.5 inches) of precipitation spread over approximately 17 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 Castle Rock

In Castle Rock in January humidity is 86%. With an average temperature of 5°C (41°F), this humidity feels like a heavy, damp blanket wrapping around you, making outdoor activities uncomfortable and travel quite challenging due to the chill combined with the stickiness in the air.

January Average Humidity in Castle Rock

This chart illustrates the average monthly humidity levels in Castle Rock, 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 Castle Rock is approximately 86%, 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 Castle Rock

In Castle Rock in January, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Castle Rock, you can visit Hourly UV Index in Castle Rock.

Maximum UV Index Levels in Castle Rock for January

The chart shows the monthly maximum UV Index (UVI) for Castle Rock 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 Castle Rock typically reaches 2, which falls under the low exposure category.

Data source: Castle Rock 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 Castle Rock Compares to Other Months

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

This table compares monthly weather conditions in Castle Rock, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	5°C (41°F)	190 mm (7.5 inches)	86%	low
February Weather	4°C (40°F)	175 mm (6.9 inches)	84%	moderate
March Weather	7°C (45°F)	150 mm (5.9 inches)	85%	moderate
April Weather	10°C (50°F)	125 mm (4.9 inches)	83%	high
May Weather	13°C (56°F)	74 mm (2.9 inches)	84%	very high
June Weather	16°C (61°F)	59 mm (2.3 inches)	84%	very high
July Weather	18°C (65°F)	10 mm (0.4 inches)	82%	very high
August Weather	19°C (66°F)	10 mm (0.4 inches)	73%	very high
September Weather	16°C (61°F)	84 mm (3.3 inches)	74%	high
October Weather	10°C (51°F)	132 mm (5.2 inches)	83%	moderate
November Weather	7°C (45°F)	179 mm (7.0 inches)	86%	moderate
December Weather	4°C (40°F)	202 mm (8.0 inches)	87%	low