September weather in St. Marks, FL
The average temperature in St. Marks in September is 79.1°F (69.6°F–88.6°F). Average precipitation: 4.91 inches.
September is a fall month in St. Marks, and is warmer than the annual average of 68.5°F. Daily temperatures swing about 19°F between overnight low and afternoon high. Expect about 9 days with precipitation. Daylight averages about 12h 10m. For travel, September is hot.
Avg High
88.6°F
Avg Low
69.6°F
Precipitation
4.91 in
Daylight
12h 10m
September records in St. Marks
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 97.0°F (1947) | 62.1°F (1992) | 1.75 in (2016) |
| September 2 | 100.9°F (2024) | 60.1°F (1999) | 5.07 in (1998) |
| September 3 | 98.1°F (1966) | 62.1°F (1968) | 3.93 in (1965) |
| September 4 | 99.0°F (1962) | 64.0°F (1946) | 2.15 in (2011) |
| September 5 | 99.0°F (2019) | 60.1°F (1994) | 2.28 in (1948) |
| September 6 | 96.1°F (1962) | 62.1°F (1994) | 3.57 in (1974) |
| September 7 | 99.0°F (2019) | 60.1°F (1988) | 3.16 in (1957) |
| September 8 | 98.1°F (1990) | 55.0°F (2011) | 6.52 in (1968) |
| September 9 | 98.1°F (1954) | 55.0°F (2011) | 3.06 in (1957) |
| September 10 | 98.1°F (1954) | 54.0°F (1969) | 2.98 in (1944) |
| September 11 | 98.1°F (1954) | 51.1°F (1969) | 2.28 in (1964) |
| September 12 | 97.0°F (1991) | 53.1°F (1940) | 2.12 in (2002) |
| September 13 | 99.0°F (1991) | 57.0°F (1969) | 1.52 in (2002) |
| September 14 | 98.1°F (1991) | 54.0°F (1969) | 2.11 in (2002) |
| September 15 | 97.0°F (1972) | 55.9°F (2025) | 1.74 in (1960) |
| September 16 | 98.1°F (1991) | 54.0°F (1940) | 5.46 in (1994) |
| September 17 | 100.0°F (2019) | 52.0°F (2001) | 2.16 in (1975) |
| September 18 | 100.9°F (2019) | 55.9°F (1967) | 3.98 in (1966) |
| September 19 | 99.0°F (2005) | 46.0°F (1981) | 2.35 in (1952) |
| September 20 | 98.1°F (1997) | 45.0°F (1981) | 4.23 in (1969) |
| September 21 | 99.0°F (1997) | 50.0°F (1981) | 8.86 in (1969) |
| September 22 | 96.1°F (1993) | 52.0°F (1983) | 7.86 in (2000) |
| September 23 | 96.1°F (1993) | 48.0°F (1982) | 2.84 in (1962) |
| September 24 | 96.1°F (2019) | 50.0°F (1990) | 4.09 in (1956) |
| September 25 | 98.1°F (2019) | 45.0°F (1990) | 3.50 in (1960) |
| September 26 | 98.1°F (2019) | 50.0°F (1975) | 3.25 in (2024) |
| September 27 | 96.1°F (1972) | 46.9°F (2001) | 2.80 in (1999) |
| September 28 | 96.1°F (1972) | 46.9°F (1983) | 4.01 in (1963) |
| September 29 | 95.0°F (2017) | 46.0°F (1962) | 5.32 in (1998) |
| September 30 | 97.0°F (2019) | 39.9°F (1967) | 2.64 in (1957) |