January Weather in Rancho Cucamonga, United States

Last updated: June 24, 2025

In January, the average temperature in Rancho Cucamonga, United States hovers around 12°C (54°F). While the minimum can dip to 0°C (32°F), you might also experience a warm maximum of 30°C (85°F). Expect about 87 mm (3.4 in) of precipitation over approximately 6 days, accompanied by an average humidity level of 74%.

January Temperature in Rancho Cucamonga

In January in Rancho Cucamonga, the average temperature is 12°C (54°F). The maximum can reach 30°C (85°F) and the minimum can be as low as 0°C (32°F). This range of temperatures makes Rancho Cucamonga an ideal destination for travelers seeking a mix of warm and cooler experiences during this time.

January Weather in Rancho Cucamonga: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Rancho Cucamonga, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Rancho Cucamonga, January typically has an average temperature of 12°C (54°F), with highs reaching up to 30°C (85°F) and lows dropping to around 0°C (32°F).

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

January Precipitation in Rancho Cucamonga

In Rancho Cucamonga in January, the precipitation amount is 87 mm (3.4 in) spread over a period of 6 days.

January Precipitation Trends in Rancho Cucamonga

The chart displays monthly precipitation patterns in Rancho Cucamonga, 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 Rancho Cucamonga, January typically receives around 87 mm (3.4 inches) of precipitation spread over approximately 6 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 Rancho Cucamonga

In Rancho Cucamonga in January, humidity is 74%. With an average temperature of 12°C (54°F), this humidity feels like a chilly embrace that can dampen your travel experience, making it essential to dress in layers and prepare for an unexpected drizzle while exploring the sights.

January Average Humidity in Rancho Cucamonga

This chart illustrates the average monthly humidity levels in Rancho Cucamonga, 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 Rancho Cucamonga is approximately 74%, 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 Rancho Cucamonga

In Rancho Cucamonga 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 Rancho Cucamonga for better planning.

Maximum UV Index Levels in Rancho Cucamonga for January

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

Data source: Rancho Cucamonga 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 Rancho Cucamonga Compares to Other Months

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

This table compares monthly weather conditions in Rancho Cucamonga, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	12°C (54°F)	87 mm (3.4 inches)	74%	moderate
February Weather	12°C (54°F)	84 mm (3.3 inches)	79%	high
March Weather	14°C (57°F)	95 mm (3.7 inches)	75%	very high
April Weather	17°C (63°F)	35 mm (1.4 inches)	70%	very high
May Weather	18°C (66°F)	23 mm (0.9 inches)	70%	very high
June Weather	23°C (73°F)	3 mm (0.1 inches)	72%	extreme
July Weather	26°C (80°F)	1 mm (0.1 inches)	73%	extreme
August Weather	26°C (80°F)	2 mm (0.1 inches)	69%	very high
September Weather	24°C (76°F)	5 mm (0.2 inches)	68%	very high
October Weather	20°C (69°F)	15 mm (0.6 inches)	67%	high
November Weather	16°C (61°F)	35 mm (1.4 inches)	68%	moderate
December Weather	12°C (54°F)	87 mm (3.4 inches)	71%	moderate