San Diego Weather in August

August is the pinnacle of summer weather for San Diego, California. Overall, this is the city's hottest and driest month.

This page gives detailed information on the typical August 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 Weather iconTemperature

77 °F August average high 25 °C
68 °F August average low 20 °C

August is San Diego's hottest month overall, with temperatures peaking from the 18th to 30. That date has daily highs averaging 78 degrees Fahrenheit (26 degrees Celsius) and nighttime lows of 68 °F (20 °C).

30 days 70 °F max. or more (21 °C)
28 days 70 °F min. or less (21 °C)

Nearly every day in August warms to over 70 °F (21 °C) in San Diego. The city averages 7 days this month when the thermometer reaches into the 80s °F (over 26 °C). Temperatures above 90 °F (32 °C) occur in August an average of once every few years.

August does not normally get colder than 60 °F (16 °C), even at night.

Rainy Weather iconRain

0 in total precipitation 0 mm
0 days of rain

August is San Diego's driest month. Most years, San Diego has no rain in August.

Sunny Weather iconSun

70 % sunshine
15 days clear skies

The sun's rays reach the ground in San Diego during 70 percent of daylight hours on average in August, for a total of 288 hours in the month. Typically on 15 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in August at San Diego lasts for 13 hours and 18 minutes a day on average. The longest day of the month is the 1st with 13 hours and 44 minutes of daylight. By the end of the month, the days have shortened to 12:51 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

74 % August average humidity

The relative humidity in San Diego during August usually peaks at 81 percent in the morning then drops to 64 percent by early afternoon.

Local Time1 am4 am7 am10 am1 pm4 pm7 pm10 pm
Humidity % 80 81 79 68 64 66 76 79

Windy Weather iconWind

7.4 mph August wind speed average 11.9 kph

August is a little windier than most other months in San Diego.

Stormy Weather iconStorms

0 days rainfall of 0.5 inches (13 mm) or more
0 days with thunderstorms in August

San Diego has a thunderstorm during August about once every three or four years.


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.

San Diego Weather
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