Weather on May 18
San Marcos, CA
55 Years of Data
Avg High
76°F
Avg Low
55°F
Warmest
2008
74°F avg
Coldest
2000
55°F avg
About This Date
May 18th in San Marcos, CA typically brings pleasant spring weather, with average highs around 76°F and lows near 55°F. Over 55 years of records, the warmest May 18th was in 2008 (74°F average), while the coldest was 2000 (55°F) — a 19°F range across recorded history. Rain or other precipitation has occurred on about 5% of May 18th dates historically, with the wettest May 18th recording 0.86" of rain. The last decade has been 1.2°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.2°F warmer on this date compared to 20-30 years ago.
Planning for May 18th in San Marcos, CA? Great weather for outdoor activities.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 68° | 56° | 62° | 0.08" | — |
| 2024 | 80° | 59° | 70° | — | — |
| 2023 | 74° | 57° | 65° | — | — |
| 2022 | 78° | 57° | 68° | — | — |
| 2021 | 74° | 57° | 65° | — | — |
| 2020 | 76° | 61° | 68° | — | — |
| 2019 | 77° | 51° | 64° | — | — |
| 2018 | 73° | 57° | 65° | — | — |
| 2017 | 78° | 55° | 67° | — | — |
| 2016 | 78° | 61° | 69° | — | — |
| 2015 | 71° | 57° | 64° | — | — |
| 2014 | 81° | 61° | 71° | — | — |
| 2013 | 73° | 59° | 66° | — | — |
| 2012 | 72° | 57° | 64° | — | — |
| 2011 | 63° | 54° | 58° | 0.86" | — |
| 2010 | 65° | 55° | 60° | — | — |
| 2009 | 69° | 60° | 65° | — | — |
| 2008warmest | 84° | 65° | 74° | — | — |
| 2007 | 64° | 58° | 61° | — | — |
| 2006 | 66° | 61° | 63° | — | — |
| 2005 | 79° | 56° | 67° | — | — |
| 2004 | 69° | 60° | 65° | — | — |
| 2003 | 80° | 33° | 57° | — | — |
| 2002 | 76° | 56° | 66° | — | — |
| 2001 | 78° | 59° | 69° | — | — |
| 2000coldest | 77° | 33° | 55° | — | — |
| 1999 | 80° | 53° | 67° | — | — |
| 1998 | 81° | 49° | 65° | — | — |
| 1997 | 79° | 63° | 71° | — | — |
| 1996 | 81° | 58° | 69° | — | — |
| 1995 | 74° | 57° | 65° | — | — |
| 1994 | 64° | 59° | 62° | 0.03" | — |
| 1993 | 78° | 58° | 68° | — | — |
| 1992 | 80° | 60° | 70° | — | — |
| 1991 | 68° | 51° | 60° | — | — |
| 1990 | 72° | 54° | 63° | — | — |
| 1989 | 73° | 57° | 65° | — | — |
| 1988 | 74° | 57° | 65° | — | — |
| 1987 | 72° | 59° | 65° | — | — |
| 1986 | 89° | 55° | 72° | — | — |
| 1985 | 77° | 50° | 64° | — | — |
| 1984 | 80° | 50° | 65° | — | — |
| 1983 | 90° | 52° | 71° | — | — |
| 1982 | 86° | 58° | 72° | — | — |
| 1981 | 82° | 50° | 66° | — | — |
| 1980 | 80° | 55° | 68° | — | — |
| 1979 | 73° | 52° | 62° | — | — |
| 1978 | 95° | 50° | 73° | — | — |
| 1977 | 72° | 44° | 58° | — | — |
| 1976 | 80° | 55° | 68° | — | — |
| 1975 | 70° | 58° | 64° | — | — |
| 1974 | 68° | 47° | 57° | — | — |
| 1973 | 79° | 56° | 67° | — | — |
| 1972 | 68° | 55° | 62° | — | — |
| 1971 | 87° | 46° | 67° | — | — |
55 years of data from ESCONDIDO #2