Weather on May 18
San Mateo, CA
55 Years of Data
Avg High
68°F
Avg Low
51°F
Warmest
1978
71°F avg
Coldest
1990
53°F avg
About This Date
May 18th in San Mateo, CA typically brings mild spring weather, with average highs around 68°F and lows near 51°F. Over 55 years of records, the warmest May 18th was in 1978 (71°F average), while the coldest was 1990 (53°F) — a 18°F range across recorded history. Rain or other precipitation has occurred on about 9% of May 18th dates historically, with the wettest May 18th recording 2.13" of rain. Temperatures on this date have remained relatively stable over the past several decades.
Temperatures on this date have remained relatively stable over the past several decades.
Planning for May 18th in San Mateo, CA? Great weather for outdoor activities.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 66° | 50° | 58° | — | — |
| 2024 | 69° | 54° | 61° | — | — |
| 2023 | 64° | 54° | 59° | — | — |
| 2022 | 77° | 50° | 64° | — | — |
| 2021 | 68° | 54° | 61° | — | — |
| 2020 | 67° | 55° | 61° | 0.13" | — |
| 2019 | 56° | 50° | 53° | 2.13" | — |
| 2018 | 64° | 55° | 60° | — | — |
| 2017 | 76° | 49° | 62° | — | — |
| 2016 | 73° | 56° | 64° | — | — |
| 2015 | 60° | 55° | 58° | — | — |
| 2014 | 68° | 57° | 63° | — | — |
| 2013 | 67° | 52° | 59° | — | — |
| 2012 | 67° | 48° | 57° | — | — |
| 2011 | 63° | 51° | 57° | — | — |
| 2010 | 66° | 53° | 60° | 0.03" | — |
| 2009 | 66° | 51° | 59° | — | — |
| 2008 | 65° | 51° | 58° | — | — |
| 2007 | 64° | 50° | 57° | — | — |
| 2006 | 64° | 51° | 58° | — | — |
| 2005 | 68° | 60° | 64° | 0.38" | — |
| 2004 | 65° | 54° | 59° | — | — |
| 2003 | 70° | 48° | 59° | — | — |
| 2002 | 60° | 50° | 55° | — | — |
| 2001 | 71° | 51° | 61° | — | — |
| 2000 | 73° | 51° | 62° | — | — |
| 1999 | 63° | 51° | 57° | — | — |
| 1998 | 68° | 48° | 58° | — | — |
| 1997 | 82° | 58° | 70° | — | — |
| 1996 | 67° | 55° | 61° | — | — |
| 1995 | 68° | 49° | 58° | — | — |
| 1994 | 67° | 50° | 58° | — | — |
| 1993 | 78° | 54° | 66° | — | — |
| 1992 | 73° | 59° | 66° | — | — |
| 1991 | 61° | 48° | 54° | — | — |
| 1990coldest | 56° | 50° | 53° | — | — |
| 1989 | 64° | 50° | 57° | — | — |
| 1988 | 68° | 50° | 59° | — | — |
| 1987 | 64° | 53° | 59° | — | — |
| 1986 | 63° | 48° | 55° | — | — |
| 1985 | 65° | 52° | 58° | — | — |
| 1984 | 70° | 49° | 59° | — | — |
| 1983 | 74° | 50° | 62° | — | — |
| 1982 | 66° | 45° | 55° | — | — |
| 1981 | 66° | 53° | 60° | 0.08" | — |
| 1980 | 65° | 48° | 56° | — | — |
| 1979 | 69° | 51° | 60° | — | — |
| 1978warmest | 91° | 52° | 71° | — | — |
| 1977 | 61° | 48° | 54° | — | — |
| 1976 | 76° | 48° | 62° | — | — |
| 1975 | 77° | 49° | 63° | — | — |
| 1974 | — | 45° | — | — | — |
| 1973 | 74° | 51° | 62° | — | — |
| 1972 | 68° | 48° | 58° | — | — |
| 1971 | 69° | 44° | 57° | — | — |
55 years of data from BURLINGAME