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May Weather in San Diego, United States

Last updated: June 24, 2025

In May, the average temperature in San Diego, United States is a warm 27°C (81°F). Expect a minimum temperature of 12°C (54°F) and a maximum soaring to 39°C (102°F). The region sees about 99 mm (3.9 in) of precipitation spread over 12 days, contributing to an average humidity level of 80%.

May Temperature in San Diego

In May in San Diego, the average temperature is 27°C (81°F), with maximums reaching 39°C (102°F) and minimums dropping as low as 12°C (54°F). This diverse temperature range makes it essential for travelers to pack accordingly, ensuring comfort whether exploring during the heat of the day or relaxing in cooler evenings.

May Weather in San Diego: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in San Diego, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Diego, May typically has an average temperature of 27°C (81°F), with highs reaching up to 39°C (102°F) and lows dropping to around 12°C (54°F).
JanFebMarAprMayJunJulAugSepOctNovDec586169748184858682756661
Data source: Temperature data for San Diego 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 San Diego

In San Diego in May, the total precipitation amount is 99 mm (3.9 in) recorded over a span of 12 days.

May Precipitation Trends in San Diego

The chart displays monthly precipitation patterns in San Diego, 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 San Diego, May typically receives around 99 mm (3.9 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec2724544199887952104443738
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in San Diego

In San Diego in May humidity is 80%. With an average temperature of 27°C (81°F), this humidity feels like a warm, enveloping blanket that clings to your skin, making travel tiring as sweat beads form quickly and the air feels thick and heavy.

May Average Humidity in San Diego

This chart illustrates the average monthly humidity levels in San Diego, 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 San Diego is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec83%79%76%77%80%73%66%65%73%76%80%86%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in San Diego

In San Diego in May, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in San Diego.

Maximum UV Index Levels in San Diego for May

The chart shows the monthly maximum UV Index (UVI) for San Diego 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 San Diego typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec6810111112121211975
Data source: San Diego 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 San Diego Compares to Other Months

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

This table compares monthly weather conditions in San Diego, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather14°C (58°F)27 mm (1.1 inches)83%high
February Weather16°C (61°F)24 mm (1.0 inches)79%very high
March Weather21°C (69°F)54 mm (2.1 inches)76%very high
April Weather24°C (75°F)41 mm (1.6 inches)77%extreme
May Weather27°C (81°F)99 mm (3.9 inches)80%extreme
June Weather29°C (84°F)88 mm (3.4 inches)73%extreme
July Weather30°C (86°F)79 mm (3.1 inches)66%extreme
August Weather30°C (87°F)52 mm (2.1 inches)65%extreme
September Weather28°C (82°F)104 mm (4.1 inches)73%extreme
October Weather24°C (76°F)44 mm (1.7 inches)76%very high
November Weather19°C (66°F)37 mm (1.4 inches)80%high
December Weather16°C (61°F)38 mm (1.5 inches)86%moderate

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