September weather in Happy Valley, OR
The average temperature in Happy Valley in September is 65.4°F (52.9°F–77.9°F). Average precipitation: 1.64 inches.
September is a fall month in Happy Valley, and is warmer than the annual average of 55.4°F. Daily temperatures swing about 25°F between overnight low and afternoon high. Daylight averages about 12h 18m. For travel, September is one of the best months of the year to visit.
Avg High
77.9°F
Avg Low
52.9°F
Precipitation
1.64 in
Daylight
12h 18m
September records in Happy Valley
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 100.0°F (1988) | 39.9°F (1973) | 1.31 in (1971) |
| September 2 | 105.1°F (1988) | 41.0°F (1956) | 1.43 in (1979) |
| September 3 | 95.0°F (2017) | 37.9°F (2019) | 1.15 in (1913) |
| September 4 | 100.9°F (1955) | 43.0°F (1965) | 0.85 in (1913) |
| September 5 | 99.0°F (2024) | 39.9°F (2019) | 0.81 in (2009) |
| September 6 | 99.0°F (1958) | 42.1°F (1983) | 1.71 in (1919) |
| September 7 | 100.9°F (1958) | 41.0°F (1960) | 0.54 in (1973) |
| September 8 | 98.1°F (1981) | 41.0°F (1980) | 0.73 in (1914) |
| September 9 | 93.9°F (1948) | 43.0°F (1980) | 1.10 in (1982) |
| September 10 | 97.0°F (2013) | 42.1°F (1952) | 0.99 in (1985) |
| September 11 | 95.0°F (1973) | 43.0°F (1952) | 0.42 in (1917) |
| September 12 | 93.9°F (1999) | 41.0°F (2010) | 0.97 in (1920) |
| September 13 | 98.1°F (1999) | 37.0°F (1970) | 0.56 in (1955) |
| September 14 | 97.0°F (1957) | 42.1°F (1970) | 0.85 in (1996) |
| September 15 | 99.0°F (1981) | 37.9°F (1970) | 0.83 in (1949) |
| September 16 | 93.9°F (1981) | 42.1°F (2021) | 0.47 in (1949) |
| September 17 | 93.9°F (1991) | 33.1°F (1965) | 1.32 in (1997) |
| September 18 | 95.0°F (2005) | 39.0°F (1965) | 1.80 in (2021) |
| September 19 | 97.0°F (1999) | 37.0°F (1965) | 1.59 in (1921) |
| September 20 | 96.1°F (1952) | 37.0°F (1949) | 1.64 in (2017) |
| September 21 | 93.9°F (1952) | 37.0°F (1960) | 1.21 in (1972) |
| September 22 | 97.0°F (1990) | 37.0°F (1956) | 0.75 in (1948) |
| September 23 | 93.0°F (1974) | 37.0°F (2000) | 1.53 in (1920) |
| September 24 | 96.1°F (1974) | 37.9°F (1970) | 1.53 in (2020) |
| September 25 | 97.0°F (1991) | 37.9°F (1948) | 0.77 in (1920) |
| September 26 | 93.9°F (1967) | 37.9°F (1972) | 1.11 in (1948) |
| September 27 | 96.1°F (2003) | 34.0°F (1972) | 1.73 in (1955) |
| September 28 | 91.0°F (1989) | 37.9°F (1983) | 0.93 in (1962) |
| September 29 | 91.0°F (1993) | 35.1°F (1950) | 1.73 in (2013) |
| September 30 | 91.9°F (1975) | 34.0°F (1950) | 1.86 in (1951) |