Weather on May 18
San Mateo, CA
55 Years of Data
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 56 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 |
|---|---|---|---|---|---|
| 2026 | 80° | 56° | 68° | — | — |
| 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° | — | — |
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.