Allentown Weather in September
Average highs run from 82°F on September 1 to 72°F on September 30, and lows from 60°F to 50°F. Normal precipitation for the month is 4.84 in over about 10 wet days.
September day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
September at a glance
- Average high
- 77°F
- Average low
- 55°F
- Precipitation
- 4.84 in
- Record high
- 99°FSep 2, 1953
- Record low
- 31°FSep 24, 1963
- Chance of a freeze
- 1%
- Days of 90°F or more
- 1.5
- Daylight
- 13 h 05 min to 11 h 48 min
- Cloud cover
- 56%
- Humidity
- 73%
- Dew point
- 55°F
- Wind
- 4.3 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| Sep 1 | 82°F | 60°F | 97°F 1980 | 42°F 1967 | 31% | 0% |
| Sep 2 | 82°F | 60°F | 99°F 1953 | 44°F 1949 | 31% | 0% |
| Sep 3 | 82°F | 59°F | 99°F 1953 | 41°F 1967 | 31% | 0% |
| Sep 4 | 81°F | 59°F | 93°F 1973 | 46°F 1987 | 31% | 0% |
| Sep 5 | 81°F | 59°F | 94°F 2018 | 44°F 1997 | 31% | 0% |
| Sep 6 | 81°F | 59°F | 96°F 1983 | 42°F 1988 | 31% | 0% |
| Sep 7 | 81°F | 58°F | 92°F 2023 | 43°F 1962 | 31% | 0% |
| Sep 8 | 80°F | 58°F | 95°F 2015 | 42°F 1962 | 31% | 0% |
| Sep 9 | 80°F | 58°F | 95°F 2015 | 42°F 1986 | 31% | 0% |
| Sep 10 | 80°F | 57°F | 96°F 1983 | 39°F 1956 | 31% | 0% |
| Sep 11 | 79°F | 57°F | 96°F 1983 | 39°F 1995 | 31% | 0% |
| Sep 12 | 79°F | 57°F | 91°F 1952 | 37°F 1967 | 31% | 0% |
| Sep 13 | 79°F | 56°F | 94°F 1952 | 39°F 1967 | 31% | 0% |
| Sep 14 | 78°F | 56°F | 91°F 2008 | 42°F 1963 | 31% | 0% |
| Sep 15 | 78°F | 56°F | 88°F 1993 | 38°F 1975 | 31% | 0% |
| Sep 16 | 78°F | 55°F | 95°F 1991 | 40°F 1966 | 31% | 0% |
| Sep 17 | 77°F | 55°F | 93°F 1991 | 39°F 1959 | 31% | 0% |
| Sep 18 | 77°F | 55°F | 90°F 1965 | 36°F 1990 | 32% | 0% |
| Sep 19 | 76°F | 54°F | 93°F 1983 | 38°F 1956 | 32% | 0% |
| Sep 20 | 76°F | 54°F | 92°F 1983 | 36°F 2020 | 32% | 0% |
| Sep 21 | 76°F | 53°F | 89°F 1965 | 33°F 2020 | 32% | 0% |
| Sep 22 | 75°F | 53°F | 93°F 1980 | 36°F 1997 | 32% | 0% |
| Sep 23 | 75°F | 53°F | 93°F 1970 | 36°F 1967 | 33% | 0% |
| Sep 24 | 74°F | 52°F | 92°F 1970 | 31°F 1963 | 33% | 0% |
| Sep 25 | 74°F | 52°F | 92°F 1970 | 33°F 1963 | 33% | 0% |
| Sep 26 | 74°F | 51°F | 90°F 1970 | 35°F 1967 | 33% | 0% |
| Sep 27 | 73°F | 51°F | 91°F 2017 | 33°F 1957 | 33% | 0% |
| Sep 28 | 73°F | 51°F | 86°F 2025 | 34°F 1957 | 33% | 0% |
| Sep 29 | 72°F | 50°F | 84°F 1948 | 32°F 2000 | 33% | 0% |
| Sep 30 | 72°F | 50°F | 87°F 1953 | 33°F 1951 | 33% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (EDT).
- September 1
- sunrise 6:29 AM, sunset 7:34 PM
- September 30
- sunrise 6:58 AM, sunset 6:46 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USW00014737 (Allentown Intl AP), public domain. Records: NOAA GHCN-Daily, station USW00014737, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.