Weather on October 21
San Mateo, CA
55 Years of Data
Avg High
70°F
Avg Low
53°F
Warmest
2019
68°F avg
Coldest
2013
54°F avg
About This Date
October 21st in San Mateo, CA typically brings pleasant fall weather, with average highs around 70°F and lows near 53°F. Over 55 years of records, the warmest October 21st was in 2019 (68°F average), while the coldest was 2013 (54°F) — a 14°F range across recorded history. Rain or other precipitation has occurred on about 9% of October 21st dates historically, with the wettest October 21st recording 1.12" 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 October 21st in San Mateo, CA? Great weather for outdoor activities.
Warming Trend
0.7°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 73° | 57° | 65° | — | — |
| 2024 | 68° | 51° | 60° | — | — |
| 2023 | 72° | 57° | 64° | — | — |
| 2022 | 67° | 52° | 59° | — | — |
| 2021 | 70° | 61° | 65° | 1.12" | — |
| 2020 | 79° | 56° | 67° | — | — |
| 2019warmest | 82° | 53° | 68° | — | — |
| 2018 | 68° | 49° | 58° | — | — |
| 2017 | 68° | 51° | 60° | — | — |
| 2016 | 73° | 57° | 65° | — | — |
| 2015 | 75° | 55° | 65° | — | — |
| 2014 | 72° | 56° | 64° | — | — |
| 2013coldest | 61° | 48° | 54° | — | — |
| 2012 | 62° | 53° | 58° | — | — |
| 2011 | 71° | 53° | 62° | — | — |
| 2010 | 71° | 62° | 67° | 0.03" | — |
| 2009 | 67° | 57° | 62° | — | — |
| 2008 | 77° | 50° | 64° | — | — |
| 2007 | 72° | 52° | 62° | — | — |
| 2006 | 81° | 54° | 67° | — | — |
| 2005 | 66° | 51° | 59° | — | — |
| 2004 | 65° | 49° | 57° | — | — |
| 2003 | 80° | 54° | 67° | — | — |
| 2002 | 63° | 51° | 57° | — | — |
| 2001 | 57° | 53° | 55° | — | — |
| 2000 | 67° | 53° | 60° | — | — |
| 1999 | 77° | 53° | 65° | — | — |
| 1998 | 79° | 52° | 65° | — | — |
| 1997 | 63° | 52° | 57° | — | — |
| 1996 | 70° | 45° | 57° | — | — |
| 1995 | 69° | 52° | 60° | — | — |
| 1994 | 73° | 47° | 60° | — | — |
| 1993 | 69° | 54° | 61° | — | — |
| 1992 | 70° | 56° | 63° | — | — |
| 1991 | 74° | 58° | 66° | — | — |
| 1990 | 78° | 50° | 64° | — | — |
| 1989 | 65° | 60° | 62° | 0.25" | — |
| 1988 | 64° | 51° | 58° | — | — |
| 1987 | 72° | 54° | 63° | — | — |
| 1986 | 70° | 51° | 60° | — | — |
| 1985 | 62° | 51° | 57° | 0.25" | — |
| 1984 | 66° | 48° | 57° | — | — |
| 1983 | 70° | 52° | 61° | — | — |
| 1982 | 71° | 57° | 64° | 0.03" | — |
| 1981 | 62° | 49° | 55° | — | — |
| 1980 | 74° | 47° | 60° | — | — |
| 1979 | 67° | 48° | 57° | — | — |
| 1978 | 70° | 51° | 60° | — | — |
| 1977 | 67° | 50° | 58° | — | — |
| 1976 | 68° | 46° | 57° | — | — |
| 1975 | 71° | 49° | 60° | — | — |
| 1974 | 78° | — | — | — | — |
| 1973 | 71° | 57° | 64° | — | — |
| 1972 | 66° | 59° | 63° | — | — |
| 1971 | 69° | 45° | 57° | — | — |
55 years of data from BURLINGAME