May Weather in Fontana, United States

Last updated: June 24, 2025

In May, the average temperature in Fontana, United States is a comfortable 18°C (66°F). However, temperatures can range from a cool 6°C (43°F) to a warm 35°C (95°F). During this time, expect about 23 mm (0.9 in) of precipitation spread across 5 days, with an average humidity level of 70%.

May Temperature in Fontana

In May in Fontana, the average temperature is 18°C (66°F). Maximums can reach 35°C (95°F), and minimums can be as low as 6°C (43°F). This diverse range of temperatures makes Fontana an ideal destination for travelers seeking both warm and cooler experiences during their visit.

May Weather in Fontana: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Fontana, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Fontana, May typically has an average temperature of 18°C (66°F), with highs reaching up to 35°C (95°F) and lows dropping to around 6°C (43°F).

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

May Precipitation in Fontana

In Fontana in May, the precipitation amount is 23 mm (0.9 in) over the course of 5 days.

May Precipitation Trends in Fontana

The chart displays monthly precipitation patterns in Fontana, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In Fontana, May typically receives around 23 mm (0.9 inches) of precipitation spread over approximately 5 days.

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

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Millimeters (mm) Inches (in)

May Humidity in Fontana

In Fontana in May humidity is 70%. With an average temperature of 18°C (66°F), this humidity feels like a warm, muggy embrace that can make outdoor activities feel sticky and tiring, often requiring frequent breaks for hydration and shade while traveling.

May Average Humidity in Fontana

This chart illustrates the average monthly humidity levels in Fontana, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in Fontana is approximately 70%, offering insight into how humid the weather typically is during this month.

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

May UV Index in Fontana

In Fontana in May, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Fontana.

Maximum UV Index Levels in Fontana for May

The chart shows the monthly maximum UV Index (UVI) for Fontana in May, 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 May, the maximum UV index in Fontana typically reaches 10, which falls under the very high exposure category.

Data source: Fontana May 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 May Weather in Fontana Compares to Other Months

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

This table compares monthly weather conditions in Fontana, showing how May’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