Climate averages 1991–2020
San Francisco weather
in May.
A mild, fairly dry month: the 6th warmest and the 5th driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
May is a mild month in San Francisco: daytime highs average 18.8°C and nights cool to about 10.4°C. By daytime temperature it is the 6th warmest of the 12 months.
Expect about 18 mm of rain on roughly 3 days, which makes May a fairly dry month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 11 min on an average May day.
The nearest other city in this atlas is Daly City (9 km away). In May its highs average 16.5°C, 2.3°C cooler than San Francisco, with 18 mm of rain.
Among the 498 cities listed in the United States, San Francisco ranks joint 453rd of 498 for the warmest May highs and joint 96th of 498 for the driest May (rainfall, lowest first). The mean May high of those 498 cities is 23.8°C; San Francisco is 5.0°C cooler than that mean.
From May to June, average highs rise by 2.2°C to 21.0°C, and monthly rainfall falls from 18 mm to 4.3 mm.
The annual picture
May in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San Francisco climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 13.6°C6.1°C | 6.1°C | 109 | 10.1 | 9.910 h |
| February | 14.6°C7.0°C | 7.0°C | 113 | 9.5 | 10.811 h |
| March | 15.7°C8.1°C | 8.1°C | 81 | 9.3 | 11.912 h |
| April | 17.0°C8.8°C | 8.8°C | 37 | 5.0 | 13.113 h |
| May, selected | 18.8°C10.4°C | 10.4°C | 18 | 2.8 | 14.214 h |
| June | 21.0°C11.7°C | 11.7°C | 4.3 | 0.8 | 14.715 h |
| July | 21.5°C12.6°C | 12.6°C | 0.3 | 0.1 | 14.515 h |
| August | 22.1°C13.2°C | 13.2°C | 0.7 | 0.1 | 13.614 h |
| September | 22.7°C13.0°C | 13.0°C | 1.5 | 0.4 | 12.512 h |
| October | 21.0°C11.8°C | 11.8°C | 24 | 3.1 | 11.311 h |
| November | 16.6°C8.7°C | 8.7°C | 56 | 6.1 | 10.210 h |
| December | 13.5°C6.3°C | 6.3°C | 108 | 10.1 | 9.610 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- Daly City in MayUnited States · 9 kmHigh 16.5°C · Low 10.0°C · 18 mm rain
- Oakland in MayUnited States · 13 kmHigh 21.7°C · Low 10.9°C · 17 mm rain
- Berkeley in MayUnited States · 17 kmHigh 21.8°C · Low 10.6°C · 17 mm rain
- San Mateo in MayUnited States · 25 kmHigh 19.3°C · Low 10.9°C · 20 mm rain
- Hayward in MayUnited States · 32 kmHigh 21.7°C · Low 10.8°C · 17 mm rain
- Redwood City in MayUnited States · 36 kmHigh 19.8°C · Low 10.9°C · 20 mm rain
- San Ramon in MayUnited States · 39 kmHigh 22.5°C · Low 10.8°C · 17 mm rain
- Vallejo in MayUnited States · 39 kmHigh 23.7°C · Low 10.7°C · 19 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for San Francisco) is explained once on the San Francisco year overview and on the Sources, method and limits page.
Daly City lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.