September weather in Sammamish, WA
The average temperature in Sammamish in September is 59.7°F (49.1°F–70.4°F). Average precipitation: 3.02 inches.
September is a fall month in Sammamish, and is warmer than the annual average of 51.7°F. Daily temperatures swing about 21.3°F between overnight low and afternoon high. Expect about 11 days with precipitation. Daylight averages about 12h 19m. For travel, September is a comfortable month to visit.
Avg High
70.4°F
Avg Low
49.1°F
Precipitation
3.02 in
Daylight
12h 19m
September records in Sammamish
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 89.1°F (1974) | 36.0°F (1984) | 1.50 in (1936) |
| September 2 | 96.1°F (1988) | 35.1°F (1932) | 1.57 in (1971) |
| September 3 | 93.9°F (1988) | 36.0°F (1932) | 1.32 in (1913) |
| September 4 | 90.0°F (2003) | 36.0°F (1912) | 2.68 in (1913) |
| September 5 | 93.0°F (1944) | 34.0°F (1947) | 1.65 in (2013) |
| September 6 | 88.0°F (1956) | 33.1°F (1901) | 0.71 in (1999) |
| September 7 | 98.1°F (1981) | 37.9°F (1901) | 2.26 in (1903) |
| September 8 | 87.1°F (1943) | 32.0°F (1928) | 1.03 in (1915) |
| September 9 | 90.0°F (1907) | 32.0°F (1901) | 1.32 in (1941) |
| September 10 | 89.1°F (1932) | 30.0°F (1984) | 0.99 in (1962) |
| September 11 | 87.1°F (1922) | 34.0°F (1901) | 1.43 in (2004) |
| September 12 | 87.1°F (1924) | 35.1°F (1970) | 1.22 in (1934) |
| September 13 | 89.1°F (1979) | 33.1°F (1970) | 1.05 in (1899) |
| September 14 | 95.0°F (1979) | 35.1°F (1916) | 1.94 in (1935) |
| September 15 | 95.0°F (1967) | 30.0°F (1901) | 1.08 in (1911) |
| September 16 | 96.1°F (1967) | 32.0°F (1936) | 2.72 in (1947) |
| September 17 | 87.1°F (1938) | 32.0°F (1901) | 1.73 in (1997) |
| September 18 | 82.9°F (1991) | 30.0°F (1901) | 1.25 in (2021) |
| September 19 | 86.0°F (1901) | 33.1°F (1983) | 1.13 in (1958) |
| September 20 | 84.9°F (1974) | 33.1°F (1949) | 1.84 in (1945) |
| September 21 | 90.0°F (1952) | 32.0°F (1932) | 1.38 in (1972) |
| September 22 | 91.9°F (1990) | 33.1°F (1955) | 1.64 in (1978) |
| September 23 | 86.0°F (1940) | 28.0°F (1901) | 1.21 in (1933) |
| September 24 | 87.1°F (1974) | 30.0°F (1948) | 1.23 in (1988) |
| September 25 | 91.9°F (1997) | 28.9°F (1908) | 1.38 in (1945) |
| September 26 | 86.0°F (1991) | 30.0°F (1908) | 1.58 in (1959) |
| September 27 | 87.1°F (1970) | 30.9°F (1934) | 1.12 in (1927) |
| September 28 | 82.0°F (1918) | 25.0°F (1929) | 1.60 in (1903) |
| September 29 | 82.0°F (2003) | 30.0°F (1983) | 2.45 in (2013) |
| September 30 | 87.1°F (1992) | 26.1°F (1901) | 1.71 in (1953) |