San Mateo County Weather in August
Average highs run from 65°F on August 1 to 66°F on August 31, and lows from 54°F to 53°F. Normal precipitation for the month is 0.23 in over about 8 wet days.
August day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
August at a glance
- Average high
- 66°F
- Average low
- 54°F
- Precipitation
- 0.23 in
- Record high
- 105°FAug 7, 1983
- Record low
- 42°FAug 30, 1939
- Chance of a freeze
- 0%
- Daylight
- 14 h 03 min to 13 h 01 min
- Cloud cover
- 59%
- Humidity
- 86%
- Dew point
- 55°F
- Wind
- 8.9 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation.
| Date | Normal high | Normal low | Record high | Record low | Chance wet |
|---|---|---|---|---|---|
| Aug 1 | 65°F | 54°F | 104°F 1993 | 46°F 1937 | 26% |
| Aug 2 | 65°F | 54°F | 103°F 1946 | 48°F 1956 | 26% |
| Aug 3 | 65°F | 54°F | 104°F 1998 | 46°F 1956 | 26% |
| Aug 4 | 65°F | 54°F | 99°F 1947 | 44°F 1934 | 26% |
| Aug 5 | 65°F | 54°F | 98°F 1964 | 44°F 1954 | 26% |
| Aug 6 | 65°F | 54°F | 103°F 1983 | 43°F 1979 | 26% |
| Aug 7 | 65°F | 54°F | 105°F 1983 | 45°F 1975 | 26% |
| Aug 8 | 65°F | 54°F | 98°F 1984 | 45°F 1934 | 25% |
| Aug 9 | 65°F | 54°F | 100°F 1970 | 46°F 1934 | 25% |
| Aug 10 | 65°F | 54°F | 99°F 1970 | 46°F 1931 | 25% |
| Aug 11 | 66°F | 54°F | 102°F 1937 | 47°F 1932 | 25% |
| Aug 12 | 66°F | 54°F | 100°F 1959 | 48°F 1932 | 24% |
| Aug 13 | 66°F | 54°F | 95°F 1935 | 48°F 1946 | 24% |
| Aug 14 | 66°F | 54°F | 103°F 2020 | 48°F 1934 | 24% |
| Aug 15 | 66°F | 54°F | 100°F 2019 | 48°F 1946 | 24% |
| Aug 16 | 66°F | 54°F | 101°F 2015 | 45°F 1932 | 23% |
| Aug 17 | 66°F | 54°F | 102°F 1939 | 43°F 1932 | 23% |
| Aug 18 | 66°F | 54°F | 99°F 1934 | 44°F 1931 | 23% |
| Aug 19 | 66°F | 54°F | 97°F 1950 | 45°F 1931 | 23% |
| Aug 20 | 66°F | 54°F | 97°F 1964 | 46°F 1932 | 22% |
| Aug 21 | 66°F | 54°F | 97°F 2025 | 47°F 1931 | 22% |
| Aug 22 | 66°F | 54°F | 96°F 1974 | 44°F 1973 | 22% |
| Aug 23 | 66°F | 54°F | 96°F 1931 | 48°F 1932 | 22% |
| Aug 24 | 66°F | 54°F | 104°F 2010 | 46°F 1955 | 21% |
| Aug 25 | 66°F | 54°F | 102°F 1988 | 45°F 1955 | 21% |
| Aug 26 | 66°F | 53°F | 101°F 1944 | 46°F 1952 | 21% |
| Aug 27 | 66°F | 53°F | 102°F 1981 | 46°F 1931 | 21% |
| Aug 28 | 66°F | 53°F | 101°F 2009 | 45°F 1933 | 21% |
| Aug 29 | 66°F | 53°F | 102°F 1968 | 45°F 1932 | 21% |
| Aug 30 | 66°F | 53°F | 101°F 1968 | 42°F 1939 | 21% |
| Aug 31 | 66°F | 53°F | 96°F 2025 | 46°F 1955 | 20% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PDT).
- August 1
- sunrise 6:14 AM, sunset 8:17 PM
- August 31
- sunrise 6:39 AM, sunset 7:40 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00043714 (Half Moon Bay), public domain. Records: NOAA GHCN-Daily, station USC00047339, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.