Weather on August 18
San Mateo, CA
55 Years of Data
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.
| 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° | — | — |
San Mateo, CA Temperature Range by Month
Average monthly highs and lows. The shaded band shows the typical daily temperature range.
San Mateo, CA Monthly Precipitation
Average rainfall per month, in inches.
San Mateo, CA Daily Temperature Calendar
Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.
Best Time to Visit San Mateo, CA
San Mateo, CA has no months that meet our "pleasant" threshold — every season has tradeoffs.