May Weather in San Francisco, United States

Last updated: February 24, 2025

In May, San Francisco experiences a delightful climate characterized by a maximum temperature of 24°C (75°F) and a comfortable average of 14°C (57°F). Nights can be cool, with temperatures dipping to a minimum of 8°C (47°F). The month typically sees low precipitation, with only 20 mm (0.8 in) of rain spread over just 2 days, making it a great time for outdoor activities. With an average humidity of 83%, the city’s coastal influence ensures a fresh and invigorating atmosphere. Ideal for exploring, May in San Francisco is punctuated by pleasant days and crisp evenings.

May Temperature in San Francisco

In May, San Francisco begins to shake off the lingering chill of spring, showcasing a delightful progression in temperatures. With a minimum of 8°C (47°F) and a comfortable average soaring to 14°C (57°F), residents and visitors alike can enjoy the blossoming outdoors. The highs peak at 24°C (75°F), offering ample opportunity for sun-soaked afternoons by the bay. This month marks a significant transition, as temperatures steadily rise—contrasting starkly with the cooler seasons. As summer approaches, the pleasant warmth of May invites everyone to explore the city's iconic sights, basking in the mild climate that makes this coastal gem so enchanting.

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.
JanFebMarAprMayJunJulAugSepOctNovDec515253555659596162605552
Data source: Temperature data for San Francisco 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 Francisco

In May, San Francisco experiences a noticeable dip in precipitation, with only 20 mm (0.8 inches) of rain falling over just 2 days. This marks a significant decline compared to the wetter months earlier in the year, such as January and February, when the city averaged over 100 mm of rain each month. Following April’s modest 35 mm, May solidifies the transition into the drier season, where rainfall becomes increasingly sparse. As the city approaches summer, the persistent sunshine begins to dominate, leading into June, which records a mere 3 mm of precipitation, hinting at the upcoming dry spell. This pattern reflects a trend of diminishing rainfall as spring progresses into summer, painting a picture of a climate that increasingly favors sunny days over the cooler, wetter months.

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.
JanFebMarAprMayJunJulAugSepOctNovDec1061097835203322305095
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in San Francisco

May in San Francisco brings a refreshing humidity of 83%, striking a delicate balance between the soaking dampness of winter and the rising warmth of summer. Following a gradual decrease from a high of 85% in January, the humidity stabilizes a bit in April at 79%, only to slightly rise again in May. This upward trend continues into June, where humidity peaks at 84%, maintaining a comfortable level as the city gears up for the more humid summer months. Overall, May serves as a transition point, blending the crisp air of spring with the upcoming warmth, all while showcasing the maritime influence that characterizes San Francisco's unique climate.

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, allowing you to see how May's humidity levels compare to other months.
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 San Francisco

As May rolls into San Francisco, residents and visitors should take note of the rising UV Index, peaking at 10, which falls within the very high exposure category. This marks a significant jump from the moderate levels seen earlier in the year, with both April and May reflecting an intensifying sun that demands caution, as burn time decreases to just 15 minutes. Following the trend of increasing UV levels, June and July will push the limits even further into the extreme zone, emphasizing the importance of sun protection. As the seasons progress, the pattern clearly illustrates the need for heightened awareness and proactive measures against UV exposure. For those looking for more details, check out the San Francisco UV Index to stay informed and safe this summer.

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.
JanFebMarAprMayJunJulAugSepOctNovDec3589101111109743
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.

May Sunshine in San Francisco

As May unfolds in San Francisco, the city basks in its transformative burst of sunshine, boasting an impressive 341 hours of daylight. This radiant month marks a significant leap from the earlier spring months, reflecting a steady increase from 296 hours in April. The trend of growing daylight continues into June, where 355 hours shine bright, indicating that San Francisco's sunny days only get better as summer approaches. This pattern of ascending hours not only invigorates the city but also invites residents and visitors alike to embrace outdoor activities, making May a delightful prelude to the sun-drenched days of summer.

Monthly Sunshine Duration in San Francisco: May Highlighted

The May sunshine duration represents the total number of hours San Francisco experiences direct sunlight during the month of May, excluding cloudy or obstructed periods. This chart compares the sunshine duration of May with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec151h216h263h296h341h355h349h320h299h276h225h194h
Data source: San Francisco May Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in San Francisco During May

May in San Francisco marks the arrival of sunnier skies, boasting a 66% chance of sun—the highest of any month so far. This uptick continues the trend from March, where the probability of sunny days approaches a comfortable 62%, and April holds steady at 56%. As spring unfolds, the city transitions away from the cooler, cloudier winter months, where January and February see their share of gloomy days with only 39% and 56% chances of sunshine, respectively. While June dips to 51%, May stands out as a refreshing peak, inviting residents and visitors alike to bask in the warmth before the typical summer fog rolls in.

Percentage of Sunny Days in May in San Francisco

The chart illustrates the percentage of sunny days in San Francisco throughout the year, with May highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often San Francisco experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec39%56%62%56%66%51%37%47%51%51%42%33%
Data source: San Francisco May chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in San Francisco in May

As spring transitions into summer, San Francisco experiences a delightful increase in daylight, particularly evident in May, when the sun graces the city with 14 hours of light. This month marks a peak in daylight hours, reflecting a growing trend that's been building since the beginning of the year. From a modest 9 hours in January to the blossoming 14 hours of May, daylight duration steadily rises, providing the perfect backdrop for outdoor activities and exploration. June continues this trend, maintaining the same generous 14 hours of sunlight, before gradually tapering off in the following months. Overall, May serves as a vibrant milestone in San Francisco's daylight journey, inviting residents and visitors alike to bask in the warmth and energy of longer, sunlit days.

Average Daylight Hours in San Francisco for May

The chart illustrates the variation in daylight duration in San Francisco throughout the year, with May highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 53m10h 48m11h 59m13h 11m14h 12m14h 42m14h 26m13h 31m12h 22m11h 9m10h 7m9h 35m
Data source: San Francisco daylight hours, calculated by summing the hours between sunrise and sunset for each day.

May Winds in San Francisco

In May, San Francisco begins to embrace the brisk embrace of spring with an average wind speed of 5.4 m/s (12 mph), marking a noticeable uptick from the preceding months. This increase reflects a transition from the relatively calmer winds of earlier seasons, as April enjoyed a gentler 4.6 m/s (10 mph). As the city moves towards summer, May's winds hint at the invigorating gales that are characteristic of the coastal climate. Following May, the winds remain moderately strong in June at 4.7 m/s (10 mph), yet start to taper off as the summer months progress. Overall, May not only stands out as a time of increased wind activity but also sets the stage for the shifting patterns that lie ahead in San Francisco's dynamic meteorological landscape.

Average May Wind Speed in San Francisco

The chart displays monthly wind speed patterns in San Francisco, with values for each month shown alongside May's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how May's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec3.24.04.14.65.4 m/s4.74.03.73.33.72.73.9
Data source: San Francisco May wind data, generated using information from the Copernicus Climate Change Service.

How May Weather in San Francisco Compares to Other Months

The weather in San Francisco changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of May's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in San Francisco and find detailed weather information for every month.

In comparing the weather of May and January, May tends to be milder with average temperatures ranging from a minimum of 8°C (47°F) to a maximum of 24°C (75°F), while January's temperatures are cooler, averaging from 3°C (38°F) to a maximum of 21°C (70°F). Precipitation levels in January are significantly higher at 106 mm (4.2 in) over 9 days, compared to only 20 mm (0.8 in) across 2 days in May. Both months feature high humidity, with January slightly higher at 85% compared to May's 83%. For more detailed insights, you can check San Francisco weather in January.

When comparing the weather in May and February, we see notable differences in temperature and precipitation. May enjoys warmer temperatures with a minimum of 8°C (47°F) and a maximum of 24°C (75°F), while February has cooler temperatures ranging from a minimum of 4°C (39°F) to a maximum of 20°C (69°F). February tends to be much wetter, with total precipitation of 109 mm (4.3 in) spread over 9 days, compared to May's much lighter 20 mm (0.8 in) over just 2 days. Humidity levels are quite similar, hovering around 82% in February and 83% in May. For more detailed information, you can check San Francisco weather in February.

In comparing the weather between March and May, May tends to be warmer and more stable. Average temperatures in May range from a minimum of 8°C (47°F) to a maximum of 24°C (75°F), whereas March experiences slightly cooler temperatures, with a minimum of 5°C (42°F) and a maximum of 20°C (69°F). Notably, May also has significantly less precipitation, averaging just 20 mm (0.8 in) over about 2 days compared to March's 78 mm (3.1 in) spread across 10 days. Humidity levels are similar, with May at 83% and March slightly lower at 82%. For more detailed information, you can check San Francisco weather in March.

In comparing the weather between April and May, we see a slight increase in average temperatures, with May averaging 14°C (57°F) compared to April's 13°C (55°F). While May features a more pleasant maximum temperature of 24°C (75°F), April boasts a higher maximum of 28°C (82°F), although this warmer month also experiences more precipitation, totaling 35 mm (1.4 in) over five days, versus May's 20 mm (0.8 in) over just two days. Additionally, humidity levels are slightly higher in May at 83%, compared to April’s 79%. For more details, visit San Francisco weather in April.

May tends to be cooler with temperatures ranging from a minimum of 8°C (47°F) to a maximum of 24°C (75°F) and an average of 14°C (57°F). It experiences a bit more precipitation, with 20 mm (0.8 in) recorded over two days, along with relatively high humidity at 83%. In contrast, June sees a rise in temperatures, with a minimum of 10°C (51°F) and a maximum of 31°C (88°F), averaging around 15°C (60°F). Notably, June experiences significantly less rain, with only 3 mm (0.1 in) and no rainy days, and the humidity increases slightly to 84%. For a detailed look at June weather specifics, you can visit San Francisco weather in June.

In May, temperatures range from a low of 8°C (47°F) to a high of 24°C (75°F), with an average of 14°C (57°F). The month experiences about 20 mm (0.8 in) of precipitation over roughly 2 days, contributing to a humidity level of 83%. In contrast, July sees slightly warmer temperatures, with a minimum of 11°C (52°F) and a maximum of 24°C (76°F), maintaining an average of 15°C (60°F). This month is notably drier, with only 3 mm (0.1 in) of precipitation over no rainy days, resulting in a higher humidity level of 87%. For more details on July weather, you can find more information here: San Francisco weather in July.

In comparing May and August weather, we can see a noticeable shift in temperatures and precipitation patterns. In May, the temperatures range from a minimum of 8°C (47°F) to a maximum of 24°C (75°F), with an average of 14°C (57°F) and moderate humidity at 83%. The month experiences some rainfall, with about 20 mm (0.8 in) over 2 days. Conversely, August brings warmer conditions, with temperatures ranging from a minimum of 11°C (53°F) to a maximum of 27°C (81°F) and an average of 16°C (61°F). Notably, August is much drier, receiving only 2 mm (0.1 in) of precipitation over 0 days, while humidity slightly increases to 87%. This creates a distinctly warmer and drier atmosphere during August, making it quite different from the early spring conditions of May. For more details, check out San Francisco weather in August.

May and September exhibit distinct weather characteristics, reflecting the transition from spring to early autumn. In May, temperatures range from a minimum of 8°C (47°F) to a maximum of 24°C (75°F), with an average of 14°C (57°F) and a modest 20 mm (0.8 in) of precipitation over just two days, resulting in a relatively humid environment with 83% humidity. In contrast, September experiences warmer conditions, with temperatures ranging from a minimum of 11°C (51°F) to a peak of 35°C (96°F), averaging 17°C (63°F). It boasts significantly lower precipitation at only 2 mm (0.1 in) without any rainy days, accompanied by a slightly higher humidity of 86%. For more on September weather patterns, visit San Francisco weather in September.

In comparing May and October weather, both months exhibit mild temperatures, but October tends to be slightly warmer. In May, temperatures range from a minimum of 8°C (47°F) to a maximum of 24°C (75°F), with an average of 14°C (57°F) and an overall humidity of 83%. In contrast, October features temperatures that start at 9°C (48°F) and go up to 28°C (84°F), averaging at 16°C (60°F) with humidity at a slightly lower 80%. While May sees about 20 mm (0.8 in) of precipitation over 2 days, October experiences a bit more rain, totaling 30 mm (1.2 in) over the same number of days. For a more detailed look at October's weather patterns, check out San Francisco weather in October.

May and November both feature mild temperatures, but May typically enjoys slightly warmer averages, with highs reaching up to 24°C (75°F) compared to November's maximum of 23°C (74°F). Precipitation is notably lower in May, with just 20 mm (0.8 in) falling over two days, whereas November sees increased rainfall of 50 mm (2.0 in) over five days. Additionally, humidity levels are slightly higher in May at 83%, compared to November's 79%. For more detailed information on this month's weather, check out San Francisco weather in November.

May and December exhibit notable contrasts in weather patterns. In May, temperatures range from a minimum of 8°C (47°F) to a maximum of 24°C (75°F), with an average of 14°C (57°F). The month sees relatively mild precipitation, totaling about 20 mm (0.8 in) over just 2 days, and the humidity sits at a higher 83%. In contrast, December experiences cooler temperatures, with a minimum of 4°C (40°F) and a maximum of 20°C (69°F), and an average of 11°C (52°F). This month is significantly wetter, receiving approximately 95 mm (3.7 in) of rain over 9 days, and the humidity drops slightly to 79%. For more specific details, you can check out San Francisco weather in December.

Compare San Francisco's Climate with Cities Worldwide

Conclusion: What to Expect From May Weather in San Francisco

As May rolls into San Francisco, the city begins to shed the cool grip of spring, welcoming warmer days and vibrant blooms. With average temperatures climbing to a pleasant 14°C (57°F) and highs reaching up to 24°C (75°F), locals and visitors alike can enjoy more outdoor activities and the stunning coastal vistas. Unlike the wetter winter months, May experiences only a couple of days of light precipitation, allowing for plenty of sunshine under a pleasantly high humidity of 83%. This transition captures the essence of San Francisco's unique microclimate, making May a delightful precursor to the warmer summer months. For a deeper understanding of what to expect throughout the year, explore the complete San Francisco Climate.