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May Weather in California, United States

Last updated: June 24, 2025

In May, the average temperature in California, United States hovers around 19°C (67°F). Temperatures can vary significantly, with a minimum of 5°C (41°F) and a maximum reaching 34°C (94°F). Be prepared for some rain, as the area sees an average precipitation of 175 mm (6.9 in) over 15 days, and expect to contend with a fairly high average humidity of 82%.

May Temperature in California

In May in California, the average temperature is 19°C (67°F). Maximum temperatures can reach 34°C (94°F), while minimums can drop as low as 5°C (41°F). Travelers should be prepared for a range of temperatures, making layering essential for comfort.

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

The chart illustrates May temperature patterns in California, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In California, May typically has an average temperature of 19°C (67°F), with highs reaching up to 34°C (94°F) and lows dropping to around 5°C (41°F).
JanFebMarAprMayJunJulAugSepOctNovDec323547546676807672584539
Data source: Temperature data for California generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in California

In California in May, the total precipitation amount is 175 mm (6.9 in) over the course of 15 days.

May Precipitation Trends in California

The chart displays monthly precipitation patterns in California, 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 California, May typically receives around 175 mm (6.9 inches) of precipitation spread over approximately 15 days.
JanFebMarAprMayJunJulAugSepOctNovDec6860114124176113115106611075638
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in California

In California in May humidity is 82%. With an average temperature of 19°C (67°F), this humidity feels like a heavy blanket wrapping around you, making each step feel sluggish and the air thick as you explore the sights.

May Average Humidity in California

This chart illustrates the average monthly humidity levels in California, 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 California is approximately 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec80%78%75%77%82%83%81%78%72%72%84%86%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in California

In California 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 California.

Maximum UV Index Levels in California for May

The chart shows the monthly maximum UV Index (UVI) for California 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 California typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3579101111109743
Data source: California 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 California Compares to Other Months

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

This table compares monthly weather conditions in California, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (33°F)68 mm (2.7 inches)80%moderate
February Weather1°C (35°F)60 mm (2.4 inches)78%moderate
March Weather8°C (47°F)114 mm (4.5 inches)75%high
April Weather12°C (55°F)124 mm (4.9 inches)77%very high
May Weather19°C (67°F)175 mm (6.9 inches)82%very high
June Weather25°C (77°F)113 mm (4.4 inches)83%extreme
July Weather26°C (80°F)115 mm (4.5 inches)81%extreme
August Weather25°C (77°F)106 mm (4.2 inches)78%very high
September Weather22°C (73°F)61 mm (2.4 inches)72%very high
October Weather14°C (58°F)107 mm (4.2 inches)72%high
November Weather7°C (45°F)56 mm (2.2 inches)84%moderate
December Weather4°C (39°F)38 mm (1.5 inches)86%moderate

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