Weather on August 18
San Mateo, CA
55 Years of Data
Avg High
72°F
Avg Low
56°F
Warmest
1978
72°F avg
Coldest
1973
57°F avg
About This Date
August 18th in San Mateo, CA typically brings pleasant summer weather, with average highs around 72°F and lows near 56°F. Over 55 years of records, the warmest August 18th was in 1978 (72°F average), while the coldest was 1973 (57°F) — a 15°F range across recorded history. Rain or other precipitation has occurred on about 4% of August 18th dates historically, with the wettest August 18th recording 0.86" of rain. The last decade has been 3.2°F warmer on this date compared to 20-30 years ago.
The last decade has been 3.2°F warmer on this date compared to 20-30 years ago.
Planning for August 18th in San Mateo, CA? Great weather for outdoor activities.
Warming Trend
0.4°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 74° | 58° | 66° | — | — |
| 2024 | 69° | 56° | 62° | — | — |
| 2023 | 80° | 63° | 71° | — | — |
| 2022 | 71° | 55° | 63° | — | — |
| 2021 | 75° | 58° | 66° | — | — |
| 2020 | 84° | 61° | 72° | — | — |
| 2019 | 75° | 61° | 68° | — | — |
| 2018 | 71° | 52° | 61° | — | — |
| 2017 | 72° | 59° | 65° | — | — |
| 2016 | 73° | 58° | 65° | — | — |
| 2015 | 76° | 59° | 67° | — | — |
| 2014 | 70° | 60° | 65° | — | — |
| 2013 | 78° | 57° | 68° | — | — |
| 2012 | 68° | 56° | 62° | — | — |
| 2011 | 66° | 55° | 61° | — | — |
| 2010 | 70° | 56° | 63° | — | — |
| 2009 | 68° | 56° | 62° | — | — |
| 2008 | 70° | 58° | 64° | — | — |
| 2007 | 70° | 57° | 63° | — | — |
| 2006 | 68° | 54° | 61° | — | — |
| 2005 | 72° | 56° | 64° | — | — |
| 2004 | 73° | 58° | 65° | — | — |
| 2003 | 71° | 59° | 65° | — | — |
| 2002 | 69° | 56° | 62° | — | — |
| 2001 | 69° | 54° | 61° | — | — |
| 2000 | 68° | 54° | 61° | — | — |
| 1999 | 66° | 57° | 62° | — | — |
| 1998 | 62° | 56° | 59° | — | — |
| 1997 | 72° | 61° | 66° | — | — |
| 1996 | 72° | 53° | 62° | — | — |
| 1995 | 82° | 51° | 67° | — | — |
| 1994 | 71° | 56° | 63° | — | — |
| 1993 | 74° | 54° | 64° | — | — |
| 1992 | 73° | 53° | 63° | — | — |
| 1991 | 68° | 57° | 63° | — | — |
| 1990 | 73° | 61° | 67° | — | — |
| 1989 | 72° | 57° | 64° | — | — |
| 1988 | 79° | 55° | 67° | — | — |
| 1987 | 73° | 56° | 64° | — | — |
| 1986 | 72° | 56° | 64° | — | — |
| 1985 | 74° | 54° | 64° | — | — |
| 1984 | 76° | 56° | 66° | — | — |
| 1983 | 72° | 59° | 65° | — | — |
| 1982 | 70° | 54° | 62° | — | — |
| 1981 | 67° | 55° | 61° | — | — |
| 1980 | 70° | 54° | 62° | — | — |
| 1979 | 70° | 54° | 62° | — | — |
| 1978warmest | 92° | 53° | 72° | — | — |
| 1977 | 70° | 56° | 63° | — | — |
| 1976 | 74° | 58° | 66° | 0.64" | — |
| 1975 | 72° | 59° | 65° | 0.86" | — |
| 1974 | 72° | 50° | 61° | — | — |
| 1973coldest | 68° | 46° | 57° | — | — |
| 1972 | 75° | 50° | 63° | — | — |
| 1971 | 73° | 50° | 62° | — | — |
55 years of data from BURLINGAME