San Diego Weather in May
May has some of the year's cloudiest weather at San Diego, California. Yet it is a month with little rain.
This page gives detailed information on the typical May temperature, precipitation, sun, humidity, wind and storms for San Diego. The numbers here are historical averages based on climate data gathered at the San Diego International Airport, located on San Diego Bay near the city center.
Temperature
| 70 °F | May average high | 21 °C |
| 60 °F | May average low | 16 °C |
| 12 days | 70 °F max. or more (21 °C) |
| 18 days | 60 °F min. or less (16 °C) |
Every day in May warms to over 60 degrees Fahrenheit (16 degrees Celsius) in San Diego. The city averages 1 day this month when the thermometer reaches into the 80s °F (over 26 °C), although days that hot don't happen every year. Temperatures above 90 °F (32 °C) can occur some years during May.
May does not normally get any colder than 50 °F (40 °C).
Rain
| 0.3 in | total precipitation | 7 mm |
| 2 days | of rain |
Most years, San Diego gets less than 0.3 inches (9 mm) of rain in May. About once every four years, the city receives no rain at all this month.
Sun
| 59 % | sunshine |
| 8 days | clear skies |
The sun's rays reach the ground in San Diego during 59 percent of daylight hours on average in May, for a total of 254 hours in the month. Typically on 8 days this month the sky is mainly clear, with at most 30 percent cloud cover. May has fewer clear days than other months.
Sunlight in May at San Diego lasts for 13 hours and 51 minutes a day on average. The shortest day of the month is the 1st with 13 hours and 29 minutes of daylight. By the end of the month, the days have lengthened to 14:10 from sunrise to sunset. These durations can vary by a minute or two from year to year.
Humidity
| 71 % | May average humidity |
The relative humidity in San Diego during May usually peaks at 77 percent just after midnight then drops to 61 percent by early afternoon.
| Local Time | 1 am | 4 am | 7 am | 10 am | 1 pm | 4 pm | 7 pm | 10 pm |
| Humidity % | 77 | 77 | 74 | 65 | 61 | 64 | 72 | 75 |
Wind
| 7.9 mph | May wind speed average | 12.7 kph |
May is the windiest month of the year at San Diego.
Storms
| 0 days | rainfall of 0.5 inches (13 mm) or more |
| 0 days | with thunderstorms in May |
May averages just one thunderstorm a decade.
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.