October weather in San Marcos, CA
The average temperature in San Marcos in October is 69.1°F (57.3°F–80.8°F). Average precipitation: 0.57 inches.
October is a fall month in San Marcos, and is warmer than the annual average of 65.8°F. Daily temperatures swing about 23.5°F between overnight low and afternoon high. Expect about 2 days with precipitation. Daylight averages about 11h 9m. For travel, October is a comfortable month to visit.
Avg High
80.8°F
Avg Low
57.3°F
Precipitation
0.57 in
Daylight
11h 9m
October records in San Marcos
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| October 1 | 106.0°F (2020) | 48.0°F (1982) | 0.42 in (1983) |
| October 2 | 105.1°F (2020) | 48.9°F (2002) | 0.23 in (1983) |
| October 3 | 102.0°F (1987) | 48.0°F (2002) | 0.00 in (1979) |
| October 4 | 105.1°F (1987) | 48.0°F (2002) | 0.43 in (2015) |
| October 5 | 100.9°F (2020) | 50.0°F (2002) | 0.58 in (2021) |
| October 6 | 98.1°F (1991) | 48.9°F (1994) | 0.33 in (2011) |
| October 7 | 99.0°F (2023) | 48.0°F (2011) | 0.44 in (1983) |
| October 8 | 96.1°F (1999) | 48.9°F (2007) | 0.25 in (2021) |
| October 9 | 102.0°F (2015) | 48.9°F (1998) | 0.55 in (1987) |
| October 10 | 105.1°F (1991) | 35.1°F (1998) | 0.62 in (1986) |
| October 11 | 99.0°F (1991) | 48.9°F (1990) | 1.37 in (1986) |
| October 12 | 100.9°F (2011) | 46.9°F (1997) | 0.44 in (2012) |
| October 13 | 99.0°F (2011) | 39.9°F (2006) | 0.35 in (2018) |
| October 14 | 97.0°F (1997) | 39.9°F (1981) | 0.38 in (2025) |
| October 15 | 99.0°F (2020) | 30.9°F (1988) | 0.02 in (1980) |
| October 16 | 100.9°F (2020) | 43.0°F (1981) | 0.07 in (2022) |
| October 17 | 100.0°F (2012) | 44.1°F (1981) | 0.50 in (2004) |
| October 18 | 96.1°F (1989) | 42.1°F (1980) | 1.11 in (2004) |
| October 19 | 93.9°F (2022) | 44.1°F (1984) | 2.04 in (2010) |
| October 20 | 96.1°F (1999) | 43.0°F (1984) | 1.26 in (1979) |
| October 21 | 96.1°F (2019) | 46.0°F (1996) | 0.16 in (2012) |
| October 22 | 99.0°F (1993) | 45.0°F (1996) | 0.35 in (1989) |
| October 23 | 100.9°F (2017) | 41.0°F (1996) | 0.28 in (1987) |
| October 24 | 104.0°F (2017) | 45.0°F (1981) | 0.05 in (1987) |
| October 25 | 100.0°F (2017) | 46.0°F (1995) | 0.23 in (2010) |
| October 26 | 96.1°F (1990) | 46.0°F (1984) | 0.25 in (2021) |
| October 27 | 91.0°F (2018) | 43.0°F (1996) | 1.95 in (2004) |
| October 28 | 91.9°F (2025) | 39.0°F (1981) | 0.30 in (2004) |
| October 29 | 98.1°F (2025) | 41.0°F (1996) | 0.51 in (2013) |
| October 30 | 93.9°F (2025) | 39.9°F (1979) | 0.56 in (1996) |
| October 31 | 91.0°F (1999) | 39.0°F (1979) | 0.75 in (1987) |