San Francisco Weather in April
April is one of the sunniest months for San Francisco, California. It is also less rainy than previous months, and has the lowest humidity of the year.
This page gives detailed information on the typical April temperature, precipitation, sun, humidity, wind and storms for San Francisco. The temperature, rainfall, sunshine and wind speed numbers here are historical averages based on climate data gathered in downtown San Francisco near the corner of Buchanan and Hermann Streets. The other measurements are averages at San Francisco International Airport, located south of the city center.
Temperature
| 63 °F | April average high | 17 °C |
| 50 °F | April average low | 10 °C |
| 21 days | 60 °F max. or more (18 °C) |
| 18 days | 50 °F min. or less (10 °C) |
Usually every day during April the temperature rises to over 50 °F (10 degrees Celsius) in San Francisco. The city averages 5 days this month when the thermometer reaches into the 70s °F (over 21 °C). Temperatures above 90 °F (32 °C) occur only rarely during April.
The thermometer dips to 60 °F (16 °C) or below every night this month. But April does not normally get as cold as 40 °F (4 °C).
Rain
| 1.6 in | total precipitation | 41 mm |
| 7 days | of rain |
Half the time, San Francisco receives 0.6 to 2.2 inches (15 to 55 mm) of rainfall in April. One in four years has drier weather, while another one in four is wetter.
Sun
| 73 % | sunshine |
| 11 days | clear skies |
The sun's rays reach the ground in San Francisco during 73 percent of daylight hours on average in April, for a total of 289 hours in the month. Typically on 11 days this month the sky is mainly clear, with at most 30 percent cloud cover.
Sunlight in April at San Francisco lasts for 13 hours and 12 minutes a day on average. The shortest day of the month is the 1st with 12 hours and 38 minutes of daylight. By the end of the month, the days have lengthened to 13:45 from sunrise to sunset. These durations can vary by a minute or two from year to year.
Humidity
| 71 % | April average humidity |
The relative humidity in San Francisco during April usually peaks at 81 percent in the morning then drops to 57 percent by early afternoon. This is the least humid month for San Francisco.
| Local Time | 1 am | 4 am | 7 am | 10 am | 1 pm | 4 pm | 7 pm | 10 pm |
| Humidity % | 80 | 81 | 78 | 65 | 57 | 59 | 71 | 76 |
Wind
| 9.5 mph | April wind speed average | 15.3 kph |
April is a little windier than most other months in San Francisco.
Storms
| 1 day | rainfall of 0.5 inches (13 mm) or more |
| 0 days | with thunderstorms in April |
About once in five years, an April thunderstorm passes through San Francisco.
Reference
The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals.