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May Weather in Millbrae, United States

Last updated: June 24, 2025

In May, the average temperature in Millbrae, United States hovers around 13°C (56°F). Expect a comfortable range, with minimum temperatures dipping to 9°C (48°F) and peaking at 21°C (69°F). Be prepared for a bit of rain, with an average precipitation of 22 mm (0.9 in) over 2 days. Additionally, the air can feel quite humid, with an average humidity of 83%.

May Temperature in Millbrae

In May in Millbrae, the average temperature is 13°C (56°F). The maximum can reach 21°C (69°F), and the minimum can be as low as 9°C (48°F). It's a great time to explore Millbrae with mild weather, perfect for outdoor activities and sightseeing.

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

The chart illustrates May temperature patterns in Millbrae, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Millbrae, May typically has an average temperature of 13°C (56°F), with highs reaching up to 21°C (69°F) and lows dropping to around 9°C (48°F).
JanFebMarAprMayJunJulAugSepOctNovDec525253545558586062595653
Data source: Temperature data for Millbrae 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 Millbrae

In Millbrae in May, the precipitation amount is 22 mm (0.9 in) over a span of 2 days.

May Precipitation Trends in Millbrae

The chart displays monthly precipitation patterns in Millbrae, 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 Millbrae, May typically receives around 22 mm (0.9 inches) of precipitation spread over approximately 2 days.
JanFebMarAprMayJunJulAugSepOctNovDec1021017834224333274892
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Millbrae

In Millbrae in May humidity is 83%. With an average temperature of 13°C (56°F), this humidity feels like a damp blanket wrapping around you, making travel a bit uncomfortable as the air feels heavy and the moisture clings to your skin.

May Average Humidity in Millbrae

This chart illustrates the average monthly humidity levels in Millbrae, 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 Millbrae is approximately 83%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%82%82%79%83%84%87%87%86%80%79%79%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Millbrae

In Millbrae 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 Millbrae.

Maximum UV Index Levels in Millbrae for May

The chart shows the monthly maximum UV Index (UVI) for Millbrae 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 Millbrae typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3589101111109743
Data source: Millbrae 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 Millbrae Compares to Other Months

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

This table compares monthly weather conditions in Millbrae, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather11°C (53°F)102 mm (4.0 inches)85%moderate
February Weather11°C (53°F)101 mm (4.0 inches)82%moderate
March Weather12°C (53°F)77 mm (3.0 inches)82%very high
April Weather12°C (55°F)34 mm (1.3 inches)79%very high
May Weather13°C (56°F)22 mm (0.9 inches)83%very high
June Weather15°C (58°F)4 mm (0.2 inches)84%extreme
July Weather15°C (59°F)3 mm (0.1 inches)87%extreme
August Weather16°C (61°F)3 mm (0.1 inches)87%very high
September Weather16°C (62°F)3 mm (0.1 inches)86%very high
October Weather15°C (60°F)27 mm (1.1 inches)80%high
November Weather13°C (56°F)48 mm (1.9 inches)79%moderate
December Weather12°C (53°F)92 mm (3.6 inches)79%moderate

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