Allentown Weather in September
Average highs run from 83°F on September 1 to 73°F on September 30, and lows from 58°F to 48°F. Normal precipitation for the month is 4.15 in over about 9 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
- 78°F
- Average low
- 54°F
- Precipitation
- 4.15 in
- Record high
- 97°FSep 8, 2023
- Record low
- 37°FSep 25, 1997
- Chance of a freeze
- 3%
- Days of 90°F or more
- 1.9
- Daylight
- 13 h 04 min to 11 h 48 min
- Cloud cover
- 55%
- Humidity
- 76%
- Dew point
- 59°F
- Wind
- 8.3 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 | 83°F | 58°F | 95°F 2010 | 54°F 2009 | 30% | 0% |
| Sep 2 | 83°F | 58°F | 94°F 2010 | 50°F 2023 | 30% | 0% |
| Sep 3 | 82°F | 58°F | 92°F 2010 | 50°F 1994 | 29% | 0% |
| Sep 4 | 82°F | 58°F | 93°F 2018 | 48°F 2024 | 29% | 0% |
| Sep 5 | 82°F | 57°F | 96°F 2023 | 47°F 1997 | 29% | 0% |
| Sep 6 | 82°F | 57°F | 94°F 2018 | 47°F 1997 | 29% | 0% |
| Sep 7 | 81°F | 57°F | 96°F 2018 | 46°F 2000 | 29% | 0% |
| Sep 8 | 81°F | 57°F | 97°F 2023 | 48°F 2000 | 29% | 0% |
| Sep 9 | 81°F | 56°F | 95°F 2023 | 44°F 2024 | 29% | 0% |
| Sep 10 | 80°F | 56°F | 93°F 2016 | 48°F 2024 | 29% | 0% |
| Sep 11 | 80°F | 56°F | 93°F 2016 | 45°F 1994 | 29% | 0% |
| Sep 12 | 80°F | 55°F | 93°F 2013 | 45°F 1994 | 29% | 0% |
| Sep 13 | 80°F | 55°F | 89°F 1998 | 45°F 1994 | 29% | 0% |
| Sep 14 | 79°F | 55°F | 91°F 2005 | 49°F 2013 | 29% | 0% |
| Sep 15 | 79°F | 54°F | 89°F 2008 | 44°F 2013 | 29% | 0% |
| Sep 16 | 78°F | 54°F | 88°F 2021 | 43°F 2001 | 29% | 0% |
| Sep 17 | 78°F | 54°F | 92°F 1998 | 45°F 2001 | 30% | 0% |
| Sep 18 | 78°F | 53°F | 85°F 2005 | 40°F 2013 | 30% | 0% |
| Sep 19 | 77°F | 53°F | 85°F 2021 | 44°F 2013 | 30% | 0% |
| Sep 20 | 77°F | 52°F | 87°F 2025 | 41°F 2020 | 30% | 0% |
| Sep 21 | 77°F | 52°F | 84°F 1997 | 43°F 2009 | 30% | 0% |
| Sep 22 | 76°F | 52°F | 86°F 1998 | 39°F 1997 | 30% | 0% |
| Sep 23 | 76°F | 51°F | 88°F 2019 | 42°F 1997 | 30% | 0% |
| Sep 24 | 75°F | 51°F | 90°F 2019 | 38°F 1998 | 31% | 0% |
| Sep 25 | 75°F | 50°F | 88°F 2017 | 37°F 1997 | 31% | 0% |
| Sep 26 | 75°F | 50°F | 88°F 2017 | 37°F 1997 | 31% | 0% |
| Sep 27 | 74°F | 50°F | 87°F 2007 | 43°F 2000 | 31% | 0% |
| Sep 28 | 74°F | 49°F | 90°F 1998 | 44°F 2000 | 31% | 0% |
| Sep 29 | 73°F | 49°F | 85°F 2019 | 42°F 2000 | 31% | 0% |
| Sep 30 | 73°F | 48°F | 81°F 2015 | 39°F 2000 | 31% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (EDT).
- September 1
- sunrise 6:26 AM, sunset 7:30 PM
- September 30
- sunrise 6:54 AM, sunset 6:42 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00283951 (Hightstown 2 W), public domain. Records: NOAA GHCN-Daily, station USC00286964, 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.