September is one of the warmer months of the year in Peoria, with average highs near 25.9°C and lows around 13.2°C (mean 19.5°C). It is about average for rainfall, averaging 76 mm of rainfall and 69% relative humidity across the period.
September is one of the warmer months of the year in Peoria. Across 45 years of records, the warmest September in Peoria was 2019 — when the month averaged 22.6°C — while the coldest was 1993 at 15.2°C. Typical September days reach 25.9°C with nights near 13.2°C. The long-term trend is warming, about 0.6°C per decade.
September is about average for rainfall in Peoria, averaging 76 mm of rainfall. The wettest September on record was 2008 with 263 mm, while the driest was 2017 at 19 mm.
Relative humidity in Peoria during September averages 69%. The most humid September was 1993 at 84%, and the least humid was 1988 at 55%.
September receives about 4.5 kWh/m²/day of solar energy in Peoria. The sunniest September was 2004 at 5.4 kWh/m²/day, and the cloudiest was 1993 at 3.5.
Average wind speed in Peoria during September is 2.5 m/s. The windiest September was 1985 at 3.2 m/s, while the calmest was 2025 at 1.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 19.1°C | 18.6°C | 19.5°C | 20.1°C | 20.7°C | +1.6°C |
| Avg High | 25.4°C | 25.0°C | 26.0°C | 26.2°C | 27.5°C | +2.1°C |
| Avg Low | 12.8°C | 12.1°C | 13.1°C | 14.1°C | 14.0°C | +1.2°C |
| Avg Rain | 78 mm | 71 mm | 80 mm | 89 mm | 57 mm | -21 mm |
September temperatures in Peoria have risen by about 2.4°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -0.1°C (1995) to a record high of 39°C (2011).
Rainfall in September is about average for rainfall, averaging 76 mm, with a wettest year of 263 mm.
One of the best times to visit Peoria
September is one of the best times to visit Peoria. Expect days averaging 25.9°C and nights around 13.2°C (mean 19.5°C) — warmer than Peoria's yearly average — with moderate rainfall (76 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 | 29.4°C | 22.0°C | 14.5°C | 35.2°C | 7.2°C | 20 mm | 57% | 1.8 m/s | 5.1 |
| 2024 | 28.5°C | 21.3°C | 14.1°C | 34.0°C | 8.7°C | 24 mm | 59% | 2.3 m/s | 4.8 |
| 2023 | 27.1°C | 21.0°C | 14.8°C | 34.2°C | 8.7°C | 90 mm | 67% | 2.2 m/s | 4.4 |
| 2022 | 26.6°C | 20.0°C | 13.5°C | 34.6°C | 4.0°C | 57 mm | 67% | 2.6 m/s | 4.7 |
| 2021 | 27.9°C | 21.2°C | 14.6°C | 32.1°C | 8.1°C | 46 mm | 68% | 2.8 m/s | 5 |
| 2020 | 25.2°C | 18.9°C | 12.6°C | 32.0°C | 5.1°C | 104 mm | 73% | 2.6 m/s | 4.1 |
| 2019 🔥 | 28.4°C | 22.6°C | 16.9°C | 33.0°C | 11.6°C | 147 mm | 75% | 2.7 m/s | 4.5 |
| 2018 | 27.3°C | 21.3°C | 15.3°C | 33.9°C | 5.1°C | 63 mm | 73% | 2.5 m/s | 4.6 |
| 2017 | 28.6°C | 21.5°C | 14.4°C | 34.6°C | 8.6°C | 19 mm | 61% | 2.4 m/s | 5 |
| 2016 | 25.6°C | 20.6°C | 15.7°C | 31.7°C | 9.5°C | 92 mm | 81% | 2.6 m/s | 4.6 |
| 2015 | 26.6°C | 20.8°C | 15.1°C | 33.4°C | 7.0°C | 95 mm | 75% | 2.5 m/s | 4.7 |
| 2014 | 23.9°C | 18.0°C | 12.0°C | 32.2°C | 5.1°C | 125 mm | 75% | 2.3 m/s | 4.7 |
| 2013 | 28.4°C | 21.3°C | 14.3°C | 36.6°C | 7.4°C | 39 mm | 65% | 2.6 m/s | 5.2 |
| 2012 | 24.4°C | 18.3°C | 12.2°C | 31.4°C | 3.4°C | 116 mm | 71% | 2.5 m/s | 4.9 |
| 2011 | 24.0°C | 17.8°C | 11.6°C | 39.0°C | 4.3°C | 82 mm | 67% | 2.8 m/s | 4.4 |
| 2010 | 24.7°C | 19.0°C | 13.3°C | 30.6°C | 6.5°C | 108 mm | 76% | 2.9 m/s | 4.6 |
| 2009 | 23.5°C | 18.0°C | 12.5°C | 27.1°C | 7.4°C | 48 mm | 80% | 2.1 m/s | 4.5 |
| 2008 🌧️ | 24.1°C | 18.8°C | 13.4°C | 31.8°C | 7.7°C | 263 mm | 81% | 2.1 m/s | 3.9 |
| 2007 | 28.4°C | 21.3°C | 14.2°C | 34.2°C | 3.3°C | 36 mm | 63% | 2.7 m/s | 5.3 |
| 2006 | 24.0°C | 17.9°C | 11.8°C | 29.8°C | 4.2°C | 77 mm | 71% | 2.5 m/s | 4.1 |
| 2005 | 29.2°C | 22.5°C | 15.8°C | 34.9°C | 4.9°C | 97 mm | 64% | 2.5 m/s | 4.6 |
| 2004 | 27.1°C | 20.3°C | 13.4°C | 30.4°C | 7.1°C | 23 mm | 66% | 2.4 m/s | 5.4 |
| 2003 | 24.0°C | 17.8°C | 11.6°C | 29.1°C | 2.3°C | 65 mm | 70% | 2.6 m/s | 4.7 |
| 2002 | 27.7°C | 20.7°C | 13.8°C | 33.4°C | 4.8°C | 36 mm | 65% | 2.3 m/s | 4.9 |
| 2001 | 25.0°C | 18.3°C | 11.6°C | 32.3°C | 2.7°C | 73 mm | 69% | 2.6 m/s | 4.8 |
| 2000 | 27.0°C | 19.8°C | 12.6°C | 36.7°C | 3.8°C | 81 mm | 63% | 3.1 m/s | 4.5 |
| 1999 | 26.6°C | 19.0°C | 11.5°C | 34.3°C | 4.5°C | 45 mm | 56% | 2.6 m/s | 4.9 |
| 1998 | 28.4°C | 21.5°C | 14.7°C | 36.0°C | 7.6°C | 36 mm | 67% | 2.4 m/s | 4.7 |
| 1997 | 25.2°C | 19.0°C | 12.7°C | 31.4°C | 7.5°C | 68 mm | 70% | 2.4 m/s | 4.5 |
| 1996 | 25.4°C | 18.8°C | 12.1°C | 32.3°C | 5.0°C | 63 mm | 65% | 2.4 m/s | 4.6 |
| 1995 | 24.0°C | 17.2°C | 10.4°C | 30.1°C | -0.1°C | 31 mm | 66% | 2.6 m/s | 4.4 |
| 1994 | 25.7°C | 19.1°C | 12.5°C | 33.4°C | 7.1°C | 56 mm | 68% | 2.2 m/s | 4.5 |
| 1993 ❄️ | 20.1°C | 15.2°C | 10.3°C | 26.4°C | 0.6°C | 192 mm | 84% | 2.7 m/s | 3.5 |
| 1992 | 23.5°C | 17.2°C | 10.9°C | 29.6°C | 0.8°C | 114 mm | 74% | 2.5 m/s | 4.3 |
| 1991 | 25.3°C | 19.0°C | 12.7°C | 33.2°C | 1.2°C | 67 mm | 64% | 2.5 m/s | 4.4 |
| 1990 | 25.9°C | 19.6°C | 13.4°C | 35.0°C | 2.9°C | 36 mm | 70% | 2.4 m/s | 4.5 |
| 1989 | 22.3°C | 16.5°C | 10.8°C | 29.5°C | 0.7°C | 130 mm | 77% | 2.3 m/s | 4.3 |
| 1988 | 28.6°C | 21.2°C | 13.9°C | 33.7°C | 7.8°C | 52 mm | 55% | 2.9 m/s | 4.6 |
| 1987 | 26.0°C | 19.4°C | 12.8°C | 32.3°C | 7.3°C | 43 mm | 68% | 2.5 m/s | 4.4 |
| 1986 | 26.3°C | 20.8°C | 15.2°C | 30.8°C | 6.2°C | 197 mm | 75% | 2.8 m/s | 3.6 |
| 1985 | 25.7°C | 19.6°C | 13.4°C | 33.9°C | 3.7°C | 41 mm | 68% | 3.2 m/s | 4.1 |
| 1984 | 24.8°C | 18.4°C | 12.1°C | 37.2°C | 0.1°C | 70 mm | 64% | 3 m/s | 3.8 |
| 1983 | 27.0°C | 19.9°C | 12.8°C | 35.9°C | 1.3°C | 67 mm | 62% | 2.7 m/s | — |
| 1982 | 24.6°C | 18.6°C | 12.7°C | 30.3°C | 4.0°C | 37 mm | 73% | 2.5 m/s | — |
| 1981 | 22.9°C | 17.2°C | 11.5°C | 28.8°C | 3.9°C | 60 mm | 78% | 2.6 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 25.9°C with lows near 13.2°C (mean 19.5°C), based on 45 years of NASA POWER data.
September averages 76 mm of rainfall in Peoria, about average for rainfall. The wettest on record was 263 mm in 2008.
The hottest September reached 39°C in 2011. The coldest dipped to -0.1°C in 1995.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.4°C. Daytime highs moved from 25°C to 27.9°C and overnight lows from 12.5°C to 14.3°C over the same span.
September is one of the warmer months of the year in Peoria and about average for rainfall, so plan for around 25.9°C daytime highs and 13.2°C at night.
Not quite — September is the 9th coolest month in Peoria, averaging 19.5°C.
For September in Peoria, pack light layers you can adjust through the day, with typical highs of 25.9°C and lows of 13.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 69% — moderately humid.
Average wind speed in September is 2.5 m/s. The windiest September on record averaged 3.2 m/s (1985).
The wettest September on record was 2008 with 263 mm. On average, September sees 76 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 Peoria 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.
