September weather in Bethlehem, PA
The average temperature in Bethlehem in September is 66.3°F (55.2°F–77.4°F). Average precipitation: 4.84 inches.
September is a fall month in Bethlehem, and is warmer than the annual average of 53.1°F. Daily temperatures swing about 22.2°F between overnight low and afternoon high. Expect about 10 days with precipitation. Daylight averages about 12h 15m. For travel, September is a comfortable month to visit.
Avg High
77.4°F
Avg Low
55.2°F
Precipitation
4.84 in
Daylight
12h 15m
September records in Bethlehem
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 97.0°F (1980) | 42.1°F (1967) | 4.15 in (2021) |
| September 2 | 99.0°F (1953) | 44.1°F (1949) | 1.63 in (2006) |
| September 3 | 99.0°F (1953) | 41.0°F (1967) | 1.32 in (1966) |
| September 4 | 93.0°F (1973) | 46.0°F (1987) | 1.88 in (2025) |
| September 5 | 93.9°F (2018) | 44.1°F (1997) | 2.91 in (1949) |
| September 6 | 96.1°F (1983) | 42.1°F (1988) | 2.09 in (2008) |
| September 7 | 91.9°F (2023) | 43.0°F (1962) | 1.49 in (2011) |
| September 8 | 95.0°F (2015) | 42.1°F (1962) | 4.86 in (1987) |
| September 9 | 95.0°F (2015) | 42.1°F (1986) | 1.43 in (1999) |
| September 10 | 96.1°F (1983) | 39.0°F (1956) | 2.75 in (1950) |
| September 11 | 96.1°F (1983) | 39.0°F (1995) | 3.02 in (1997) |
| September 12 | 91.0°F (1952) | 37.0°F (1967) | 3.28 in (1960) |
| September 13 | 93.9°F (1952) | 39.0°F (1967) | 1.70 in (1971) |
| September 14 | 91.0°F (2008) | 42.1°F (1963) | 3.24 in (1973) |
| September 15 | 88.0°F (1993) | 37.9°F (1975) | 3.23 in (2003) |
| September 16 | 95.0°F (1991) | 39.9°F (1966) | 6.37 in (1999) |
| September 17 | 93.0°F (1991) | 39.0°F (1959) | 1.83 in (1958) |
| September 18 | 90.0°F (1965) | 36.0°F (1990) | 4.59 in (2004) |
| September 19 | 93.0°F (1983) | 37.9°F (1956) | 1.61 in (1989) |
| September 20 | 91.9°F (1983) | 36.0°F (2020) | 1.72 in (1989) |
| September 21 | 89.1°F (1965) | 33.1°F (2020) | 3.21 in (1979) |
| September 22 | 93.0°F (1980) | 36.0°F (1997) | 1.00 in (1990) |
| September 23 | 93.0°F (1970) | 36.0°F (1967) | 1.94 in (1975) |
| September 24 | 91.9°F (1970) | 30.9°F (1963) | 2.04 in (1975) |
| September 25 | 91.9°F (1970) | 33.1°F (1963) | 1.48 in (1991) |
| September 26 | 90.0°F (1970) | 35.1°F (1967) | 2.00 in (1985) |
| September 27 | 91.0°F (2017) | 33.1°F (1957) | 5.85 in (1985) |
| September 28 | 86.0°F (2025) | 34.0°F (1957) | 3.83 in (2008) |
| September 29 | 84.0°F (1948) | 32.0°F (2000) | 1.82 in (1963) |
| September 30 | 87.1°F (1953) | 33.1°F (1951) | 5.73 in (2010) |