September weather in Monroe, WA
The average temperature in Monroe in September is 58.1°F (47.6°F–68.7°F). Average precipitation: 2.73 inches.
September is a fall month in Monroe, and is warmer than the annual average of 49.5°F. Daily temperatures swing about 21.1°F between overnight low and afternoon high. Expect about 11 days with precipitation. Daylight averages about 12h 20m. For travel, September is a comfortable month to visit.
Avg High
68.7°F
Avg Low
47.6°F
Precipitation
2.73 in
Daylight
12h 20m
September records in Monroe
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 88.0°F (1987) | 39.9°F (2021) | 2.00 in (2008) |
| September 2 | 95.0°F (1988) | 39.0°F (1932) | 1.70 in (1971) |
| September 3 | 93.9°F (1988) | 37.9°F (1932) | 0.98 in (1994) |
| September 4 | 88.0°F (1963) | 39.9°F (2010) | 1.15 in (1945) |
| September 5 | 93.9°F (1944) | 37.0°F (1947) | 2.20 in (1931) |
| September 6 | 93.9°F (1944) | 41.0°F (1956) | 1.50 in (1985) |
| September 7 | 93.9°F (1981) | 37.9°F (1992) | 1.35 in (2009) |
| September 8 | 90.0°F (1981) | 37.9°F (1992) | 1.10 in (2019) |
| September 9 | 86.0°F (1963) | 36.0°F (1970) | 1.68 in (2019) |
| September 10 | 89.1°F (1932) | 37.0°F (1962) | 2.03 in (1982) |
| September 11 | 86.0°F (2013) | 37.9°F (1988) | 1.50 in (2018) |
| September 12 | 84.9°F (1961) | 33.1°F (1970) | 0.80 in (1934) |
| September 13 | 86.0°F (1961) | 30.0°F (1970) | 0.68 in (2004) |
| September 14 | 97.0°F (1979) | 36.0°F (1971) | 1.60 in (1935) |
| September 15 | 89.1°F (1967) | 35.1°F (1969) | 1.90 in (1968) |
| September 16 | 91.9°F (2025) | 36.0°F (1965) | 0.80 in (1944) |
| September 17 | 84.0°F (1938) | 35.1°F (1971) | 1.24 in (1964) |
| September 18 | 86.0°F (1991) | 36.0°F (1947) | 1.04 in (1969) |
| September 19 | 84.0°F (1999) | 36.0°F (1942) | 1.03 in (1981) |
| September 20 | 84.9°F (1974) | 35.1°F (1983) | 1.98 in (1977) |
| September 21 | 87.1°F (1952) | 32.0°F (1932) | 1.69 in (1972) |
| September 22 | 93.9°F (1990) | 35.1°F (1932) | 1.77 in (2018) |
| September 23 | 86.0°F (1940) | 33.1°F (1931) | 1.17 in (1986) |
| September 24 | 86.0°F (1943) | 34.0°F (1948) | 1.07 in (2014) |
| September 25 | 84.9°F (1943) | 30.9°F (1933) | 1.53 in (1988) |
| September 26 | 84.0°F (2022) | 35.1°F (1934) | 0.94 in (1956) |
| September 27 | 91.0°F (1967) | 33.1°F (1929) | 1.00 in (2023) |
| September 28 | 88.0°F (2017) | 33.1°F (1984) | 1.09 in (1948) |
| September 29 | 88.0°F (1992) | 32.0°F (1985) | 0.84 in (1981) |
| September 30 | 81.0°F (1957) | 32.0°F (1950) | 1.48 in (1953) |