September weather in Watertown, SD
The average temperature in Watertown in September is 60.1°F (48.6°F–71.6°F). Average precipitation: 2.45 inches.
September is a fall month in Watertown, and is warmer than the annual average of 43°F. Daily temperatures swing about 23°F between overnight low and afternoon high. Expect about 9 days with precipitation. Daylight averages about 12h 18m. For travel, September is a comfortable month to visit.
Avg High
71.6°F
Avg Low
48.6°F
Precipitation
2.45 in
Daylight
12h 18m
September records in Watertown
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 93.0°F (1898) | 34.0°F (1946) | 2.87 in (2006) |
| September 2 | 98.1°F (1913) | 36.0°F (1974) | 1.57 in (2021) |
| September 3 | 100.9°F (1893) | 30.0°F (1974) | 1.46 in (1913) |
| September 4 | 100.9°F (1933) | 32.0°F (1902) | 1.69 in (1949) |
| September 5 | 99.0°F (1945) | 33.1°F (1929) | 1.57 in (1948) |
| September 6 | 100.9°F (1893) | 32.0°F (1929) | 1.12 in (2007) |
| September 7 | 100.9°F (1933) | 34.0°F (1899) | 1.47 in (1976) |
| September 8 | 98.1°F (1931) | 30.0°F (1907) | 2.42 in (1985) |
| September 9 | 102.9°F (1931) | 27.0°F (1898) | 2.05 in (1900) |
| September 10 | 104.0°F (1931) | 26.1°F (1898) | 2.02 in (1933) |
| September 11 | 96.1°F (1931) | 25.0°F (1898) | 2.47 in (1903) |
| September 12 | 96.1°F (1990) | 24.1°F (1902) | 1.52 in (2005) |
| September 13 | 96.1°F (1939) | 25.0°F (1902) | 1.52 in (1914) |
| September 14 | 96.1°F (1939) | 32.0°F (1910) | 2.30 in (1928) |
| September 15 | 96.1°F (1955) | 28.9°F (1916) | 2.56 in (2010) |
| September 16 | 90.0°F (1925) | 25.0°F (1903) | 2.35 in (1921) |
| September 17 | 93.0°F (1988) | 24.1°F (1900) | 1.07 in (1942) |
| September 18 | 91.9°F (1920) | 23.0°F (1929) | 2.85 in (1915) |
| September 19 | 93.0°F (1984) | 24.1°F (1918) | 1.79 in (1988) |
| September 20 | 91.0°F (1941) | 19.9°F (1918) | 1.14 in (2004) |
| September 21 | 97.0°F (1936) | 23.0°F (1934) | 1.24 in (1977) |
| September 22 | 99.0°F (1936) | 21.0°F (1974) | 1.13 in (2004) |
| September 23 | 95.0°F (1935) | 23.0°F (1983) | 2.40 in (1977) |
| September 24 | 91.0°F (1935) | 24.1°F (1942) | 2.93 in (1934) |
| September 25 | 87.1°F (1938) | 21.0°F (1926) | 1.30 in (1912) |
| September 26 | 91.0°F (1974) | 19.9°F (1965) | 1.26 in (1908) |
| September 27 | 93.0°F (1956) | 19.9°F (1942) | 1.07 in (2013) |
| September 28 | 88.0°F (1897) | 19.0°F (1942) | 0.78 in (2013) |
| September 29 | 88.0°F (2025) | 9.0°F (1899) | 1.05 in (1965) |
| September 30 | 87.1°F (1932) | 19.9°F (1939) | 1.60 in (1995) |