September is one of the warmer months of the year in State College, with average highs near 23.3°C and lows around 10.8°C (mean 17.1°C). It is about average for rainfall, averaging 96 mm of rainfall and 73% relative humidity across the period.
September is one of the warmer months of the year in State College. Across 45 years of records, the warmest September in State College was 2016 — when the month averaged 19.9°C — while the coldest was 1984 at 14.4°C. Typical September days reach 23.3°C with nights near 10.8°C. The long-term trend is warming, about 0.6°C per decade.
September is about average for rainfall in State College, averaging 96 mm of rainfall. The wettest September on record was 2018 with 233 mm, while the driest was 1984 at 34 mm.
Relative humidity in State College during September averages 73%. The most humid September was 2018 at 88%, and the least humid was 1995 at 61%.
September receives about 4.1 kWh/m²/day of solar energy in State College. The sunniest September was 2007 at 5.1 kWh/m²/day, and the cloudiest was 2011 at 3.
Average wind speed in State College during September is 0.1 m/s. The windiest Septembers were 2023, 2024 and 2025, among others at 0.1 m/s, while the calmest were 2011, 2018 and 2021, among others at 0 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 16.3°C | 16.3°C | 17.0°C | 18.1°C | 17.7°C | +1.4°C |
| Avg High | 22.6°C | 22.6°C | 23.2°C | 24.3°C | 23.8°C | +1.2°C |
| Avg Low | 9.9°C | 10.1°C | 10.8°C | 11.9°C | 11.7°C | +1.8°C |
| Avg Rain | 83 mm | 102 mm | 98 mm | 99 mm | 97 mm | +14 mm |
September temperatures in State College have risen by about 1.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -1.5°C (2000) to a record high of 34°C (2002).
Rainfall in September is about average for rainfall, averaging 96 mm, with a wettest year of 233 mm.
One of the best times to visit State College
September is one of the best times to visit State College. Expect days averaging 23.3°C and nights around 10.8°C (mean 17.1°C) — warmer than State College's yearly average — with higher rainfall (96 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 26.0°C | 19.1°C | 12.3°C | 30.1°C | 6.1°C | 55 mm | 64% | 0.1 m/s | 4.4 |
| 2024 | 23.6°C | 17.9°C | 12.2°C | 29.1°C | 6.1°C | 59 mm | 75% | 0.1 m/s | 4.1 |
| 2023 | 23.3°C | 17.4°C | 11.6°C | 33.1°C | 6.0°C | 83 mm | 77% | 0.1 m/s | 4.3 |
| 2022 | 22.4°C | 17.0°C | 11.6°C | 29.5°C | 2.6°C | 120 mm | 78% | 0.1 m/s | 4.1 |
| 2021 | 22.6°C | 17.0°C | 11.5°C | 27.6°C | 6.1°C | 210 mm | 82% | 0 m/s | 4.3 |
| 2020 | 24.6°C | 17.7°C | 10.8°C | 31.9°C | 1.5°C | 53 mm | 66% | 0.1 m/s | 4.1 |
| 2019 | 25.5°C | 18.9°C | 12.3°C | 30.7°C | 6.8°C | 35 mm | 72% | 0.1 m/s | 4.4 |
| 2018 🌧️ | 23.0°C | 18.5°C | 14.0°C | 30.6°C | 4.9°C | 233 mm | 88% | 0 m/s | 3.1 |
| 2017 | 24.5°C | 18.1°C | 11.8°C | 32.6°C | 4.7°C | 41 mm | 71% | 0.1 m/s | 4.4 |
| 2016 🔥 | 26.7°C | 19.9°C | 13.0°C | 32.6°C | 5.4°C | 71 mm | 65% | 0.1 m/s | 4.5 |
| 2015 | 26.0°C | 19.4°C | 12.9°C | 33.5°C | 6.2°C | 87 mm | 69% | 0.1 m/s | 4.4 |
| 2014 | 23.6°C | 17.1°C | 10.5°C | 30.3°C | 3.9°C | 37 mm | 72% | 0.1 m/s | 4.4 |
| 2013 | 23.5°C | 16.3°C | 9.1°C | 32.2°C | 1.6°C | 51 mm | 68% | 0.1 m/s | 4.7 |
| 2012 | 23.3°C | 17.1°C | 10.9°C | 32.8°C | 3.1°C | 104 mm | 71% | 0.1 m/s | 4.2 |
| 2011 | 22.0°C | 17.3°C | 12.7°C | 33.1°C | 2.7°C | 204 mm | 87% | 0 m/s | 3 |
| 2010 | 24.5°C | 17.9°C | 11.3°C | 33.4°C | 5.5°C | 124 mm | 64% | 0.1 m/s | 4.5 |
| 2009 | 22.0°C | 16.4°C | 10.9°C | 27.5°C | 4.4°C | 71 mm | 73% | 0.1 m/s | 3.9 |
| 2008 | 24.0°C | 17.7°C | 11.3°C | 31.9°C | 5.0°C | 75 mm | 72% | 0.1 m/s | 4.2 |
| 2007 | 25.3°C | 18.2°C | 11.0°C | 32.0°C | 2.7°C | 37 mm | 69% | 0.1 m/s | 5.1 |
| 2006 | 19.3°C | 14.7°C | 10.1°C | 24.9°C | 2.2°C | 130 mm | 84% | 0.1 m/s | 3.4 |
| 2005 | 26.3°C | 19.1°C | 11.9°C | 31.8°C | 3.5°C | 46 mm | 63% | 0.1 m/s | 4.8 |
| 2004 | 22.6°C | 17.2°C | 11.7°C | 26.4°C | 3.7°C | 224 mm | 83% | 0.1 m/s | 4 |
| 2003 | 21.0°C | 15.8°C | 10.7°C | 25.3°C | 3.9°C | 158 mm | 84% | 0 m/s | 3.6 |
| 2002 | 25.8°C | 18.9°C | 11.9°C | 34.0°C | 5.6°C | 89 mm | 63% | 0.1 m/s | 4.3 |
| 2001 | 23.1°C | 16.1°C | 9.0°C | 31.0°C | 3.2°C | 62 mm | 64% | 0.1 m/s | 4.7 |
| 2000 | 22.7°C | 15.9°C | 9.0°C | 31.3°C | -1.5°C | 86 mm | 70% | 0 m/s | 4.2 |
| 1999 | 24.2°C | 17.5°C | 10.9°C | 32.5°C | 2.9°C | 107 mm | 67% | 0.1 m/s | 4.1 |
| 1998 | 25.7°C | 18.5°C | 11.3°C | 32.0°C | 2.6°C | 60 mm | 66% | 0.1 m/s | 4.6 |
| 1997 | 21.9°C | 15.7°C | 9.5°C | 28.7°C | 2.3°C | 94 mm | 72% | 0.1 m/s | 4.2 |
| 1996 | 20.7°C | 15.9°C | 11.1°C | 28.4°C | 5.5°C | 223 mm | 84% | 0.1 m/s | 3.7 |
| 1995 | 23.5°C | 16.4°C | 9.4°C | 30.7°C | 0.8°C | 40 mm | 61% | 0 m/s | 4.1 |
| 1994 | 20.8°C | 15.1°C | 9.5°C | 26.8°C | 4.4°C | 62 mm | 78% | 0.1 m/s | 4.2 |
| 1993 | 22.1°C | 16.3°C | 10.5°C | 29.9°C | 1.7°C | 134 mm | 74% | 0.1 m/s | 3.3 |
| 1992 | 21.9°C | 15.7°C | 9.5°C | 28.5°C | 0.7°C | 98 mm | 77% | 0 m/s | 3.8 |
| 1991 | 23.4°C | 16.3°C | 9.2°C | 32.2°C | 0.5°C | 82 mm | 63% | 0.1 m/s | 4.1 |
| 1990 | 21.5°C | 15.8°C | 10.0°C | 28.5°C | -0.4°C | 121 mm | 79% | 0.1 m/s | 3.9 |
| 1989 | 22.7°C | 16.6°C | 10.5°C | 29.9°C | 0.3°C | 97 mm | 76% | 0 m/s | 3.5 |
| 1988 | 22.1°C | 15.3°C | 8.5°C | 26.0°C | 3.5°C | 95 mm | 73% | 0.1 m/s | 4.1 |
| 1987 | 21.3°C | 16.2°C | 11.0°C | 26.0°C | 2.5°C | 136 mm | 82% | 0.1 m/s | 3.7 |
| 1986 | 23.4°C | 17.2°C | 11.0°C | 29.4°C | 1.6°C | 92 mm | 73% | 0.1 m/s | 3.9 |
| 1985 | 24.4°C | 17.5°C | 10.5°C | 31.0°C | 3.0°C | 57 mm | 66% | 0.1 m/s | 4.5 |
| 1984 ❄️ | 21.0°C | 14.4°C | 7.8°C | 27.7°C | 1.2°C | 34 mm | 74% | 0.1 m/s | 4.5 |
| 1983 | 24.6°C | 17.3°C | 10.0°C | 31.9°C | 1.5°C | 62 mm | 63% | 0.1 m/s | — |
| 1982 | 23.2°C | 16.7°C | 10.3°C | 29.4°C | 3.6°C | 77 mm | 70% | 0.1 m/s | — |
| 1981 | 21.1°C | 15.3°C | 9.6°C | 26.9°C | 1.5°C | 95 mm | 77% | 0.1 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 23.3°C with lows near 10.8°C (mean 17.1°C), based on 45 years of NASA POWER data.
September averages 96 mm of rainfall in State College, about average for rainfall. The wettest on record was 233 mm in 2018.
The hottest September reached 34°C in 2002. The coldest dipped to -1.5°C in 2000.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.5°C. Daytime highs moved from 22.9°C to 23.6°C and overnight lows from 9.6°C to 11.8°C over the same span.
September is one of the warmer months of the year in State College and about average for rainfall, so plan for around 23.3°C daytime highs and 10.8°C at night.
Not quite — September is the 9th coolest month in State College, averaging 17.1°C.
For September in State College, pack light layers you can adjust through the day, with typical highs of 23.3°C and lows of 10.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 73% — moderately humid.
Average wind speed in September is 0.1 m/s. The windiest September on record averaged 0.1 m/s (1981).
The wettest September on record was 2018 with 233 mm. On average, September sees 96 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in State College behaves each September, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for September specifically, along with year-by-year records and how the month has changed over the decades.
