May Weather in San Francisco, Peru

Last updated: August 27, 2025

In May, the average temperature in San Francisco, Peru hovers around 19°C (66°F), offering a delightful climate. Expect minimums of 14°C (57°F), while highs can reach up to 24°C (76°F). While you enjoy the pleasant weather, be aware of a slight chance of rain, with an average precipitation of 4 mm (0.2 in) over just 1 day. The air carries a comfortable 83% humidity, adding a touch of warmth to your experience.

May Temperature in San Francisco

In May in San Francisco, the average temperature is 19°C (66°F). Maximums can reach 24°C (76°F) and minimums can be as low as 14°C (57°F). This mild climate makes San Francisco a perfect destination for outdoor activities and sightseeing.

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

The chart illustrates May temperature patterns in 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 San Francisco, May typically has an average temperature of 19°C (66°F), with highs reaching up to 24°C (76°F) and lows dropping to around 14°C (57°F).

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

May Precipitation in San Francisco

In San Francisco in May, the precipitation amount is 4 mm (0.2 in) during 1 day.

May Precipitation Trends in San Francisco

The chart displays monthly precipitation patterns in 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 San Francisco, May typically receives around 4 mm (0.2 inches) of precipitation spread over approximately 1 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 San Francisco

In San Francisco in May, humidity is 83%. With an average temperature of 19°C (66°F), this humidity feels like a heavy blanket wrapping around you, making travel feel more sluggish and muggy, yet there's a refreshing coolness in the air that invites you to explore.

May Average Humidity in San Francisco

This chart illustrates the average monthly humidity levels in 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 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 San Francisco

In San Francisco 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 Francisco.

Maximum UV Index Levels in San Francisco for May

The chart shows the monthly maximum UV Index (UVI) for 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 San Francisco typically reaches 11, which falls under the extreme exposure category.

Data source: 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 San Francisco Compares to Other Months

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

This table compares monthly weather conditions in 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	20°C (69°F)	73 mm (2.9 inches)	89%	extreme
February Weather	21°C (69°F)	84 mm (3.3 inches)	89%	extreme
March Weather	21°C (70°F)	58 mm (2.3 inches)	90%	extreme
April Weather	20°C (68°F)	20 mm (0.8 inches)	89%	extreme
May Weather	19°C (66°F)	4 mm (0.2 inches)	83%	extreme
June Weather	18°C (65°F)	1 mm (0.1 inches)	69%	very high
July Weather	18°C (64°F)	1 mm (0.0 inches)	56%	extreme
August Weather	18°C (64°F)	0 mm (0.0 inches)	50%	extreme
September Weather	18°C (64°F)	2 mm (0.1 inches)	53%	extreme
October Weather	18°C (65°F)	5 mm (0.2 inches)	68%	extreme
November Weather	19°C (66°F)	5 mm (0.2 inches)	81%	extreme
December Weather	19°C (67°F)	13 mm (0.5 inches)	87%	extreme