May Weather in South San Francisco, United States

Last updated: June 24, 2025

The average temperature in South San Francisco, United States during May is a mild 14°C (57°F). Expect a minimum of 8°C (47°F) and a maximum of 24°C (75°F), making it a comfortable time to explore. Be prepared for 20 mm (0.8 in) of precipitation over 2 days, and enjoy the fresh air with an average humidity of 83%.

May Temperature in South San Francisco

In May in South San Francisco, the average temperature is 14°C (57°F). Maximums can reach 24°C (75°F) and minimums can be as low as 8°C (47°F). This pleasant temperature range makes it an ideal time for outdoor activities and exploring the local attractions.

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

The chart illustrates May temperature patterns in South San Francisco, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In South San Francisco, May typically has an average temperature of 14°C (57°F), with highs reaching up to 24°C (75°F) and lows dropping to around 8°C (47°F).

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

May Precipitation in South San Francisco

In South San Francisco in May, the precipitation amount is 20 mm (0.8 in) over the course of 2 days.

May Precipitation Trends in South San Francisco

The chart displays monthly precipitation patterns in South San Francisco, 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 South San Francisco, May typically receives around 20 mm (0.8 inches) of precipitation spread over approximately 2 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 South San Francisco

In South San Francisco in May, humidity is 83%. With an average temperature of 14°C (57°F), this humidity feels like you're stepping into a warm, damp embrace that can make outdoor activities quite uncomfortable, often leaving you sweaty and exhausted if you're not prepared with plenty of water and breathable clothing.

May Average Humidity in South San Francisco

This chart illustrates the average monthly humidity levels in South San Francisco, 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 South San Francisco is approximately 83%, 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 South San Francisco

In South San Francisco 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 South San Francisco.

Maximum UV Index Levels in South San Francisco for May

The chart shows the monthly maximum UV Index (UVI) for South San Francisco 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 South San Francisco typically reaches 10, which falls under the very high exposure category.

Data source: South San Francisco 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 South San Francisco Compares to Other Months

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

This table compares monthly weather conditions in South San Francisco, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	11°C (52°F)	106 mm (4.2 inches)	85%	moderate
February Weather	11°C (52°F)	109 mm (4.3 inches)	82%	moderate
March Weather	12°C (53°F)	78 mm (3.1 inches)	82%	very high
April Weather	13°C (55°F)	35 mm (1.4 inches)	79%	very high
May Weather	14°C (57°F)	20 mm (0.8 inches)	83%	very high
June Weather	15°C (60°F)	3 mm (0.1 inches)	84%	extreme
July Weather	15°C (60°F)	3 mm (0.1 inches)	87%	extreme
August Weather	16°C (61°F)	2 mm (0.1 inches)	87%	very high
September Weather	17°C (63°F)	2 mm (0.1 inches)	86%	very high
October Weather	16°C (60°F)	30 mm (1.2 inches)	80%	high
November Weather	13°C (56°F)	50 mm (2.0 inches)	79%	moderate
December Weather	11°C (52°F)	95 mm (3.7 inches)	79%	moderate