October is one of the warmer months of the year in Chicago, with average highs near 15.1°C and lows around 9.3°C (mean 12.2°C). It is about average for rainfall, averaging 90 mm of rainfall and 76% relative humidity across the period.
October is one of the warmer months of the year in Chicago. Across 45 years of records, the warmest October in Chicago was 2021 — when the month averaged 15.9°C — while the coldest was 1987 at 8.8°C. Typical October days reach 15.1°C with nights near 9.3°C. The long-term trend is warming, about 0.8°C per decade.
October is about average for rainfall in Chicago, averaging 90 mm of rainfall. The wettest October on record was 2017 with 221 mm, while the driest was 2005 at 33 mm.
Relative humidity in Chicago during October averages 76%. The most humid October was 1986 at 84%, and the least humid was 2024 at 64%.
October receives about 3 kWh/m²/day of solar energy in Chicago. The sunniest October was 2024 at 3.8 kWh/m²/day, and the cloudiest were 1984 and 2009 at 2.2.
Average wind speed in Chicago during October is 4.9 m/s. The windiest October was 2012 at 5.7 m/s, while the calmest was 1982 at 4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 10.9°C | 11.5°C | 12.2°C | 12.8°C | 14.0°C | +3.1°C |
| Avg High | 13.9°C | 14.6°C | 15.0°C | 15.6°C | 16.9°C | +3°C |
| Avg Low | 7.9°C | 8.4°C | 9.5°C | 10.0°C | 11.1°C | +3.2°C |
| Avg Rain | 73 mm | 90 mm | 92 mm | 103 mm | 87 mm | +14 mm |
October temperatures in Chicago have risen by about 3.2°C between 1981–1985 and 2021–2025.
October has ranged from a record low of -1°C (1981) to a record high of 28.4°C (2025).
Rainfall in October is about average for rainfall, averaging 90 mm, with a wettest year of 221 mm.
A good time to visit Chicago
October is a good time to visit Chicago, with days averaging 15.1°C and nights around 9.3°C (mean 12.2°C, warmer than Chicago's yearly average) and higher rainfall. August and July are marginally more temperate, but October still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 17.7°C | 15.1°C | 12.5°C | 28.4°C | 6.7°C | 64 mm | 71% | 4.7 m/s | 3.3 |
| 2024 | 19.1°C | 15.7°C | 12.4°C | 25.1°C | 7.2°C | 40 mm | 64% | 5.1 m/s | 3.8 |
| 2023 | 16.5°C | 13.7°C | 11.0°C | 26.1°C | 2.0°C | 96 mm | 76% | 5.1 m/s | 2.7 |
| 2022 | 15.6°C | 12.4°C | 9.2°C | 21.5°C | 2.9°C | 70 mm | 71% | 5 m/s | 3.4 |
| 2021 🔥 | 18.4°C | 15.9°C | 13.5°C | 26.2°C | 7.9°C | 172 mm | 79% | 4.6 m/s | 2.5 |
| 2020 | 14.2°C | 11.2°C | 8.1°C | 22.5°C | 1.8°C | 81 mm | 75% | 5 m/s | 2.8 |
| 2019 | 13.9°C | 11.1°C | 8.3°C | 24.3°C | 0.1°C | 148 mm | 81% | 4.8 m/s | 2.8 |
| 2018 | 14.8°C | 12.1°C | 9.4°C | 25.7°C | 2.2°C | 115 mm | 79% | 5 m/s | 2.9 |
| 2017 🌧️ | 17.0°C | 14.1°C | 11.3°C | 24.5°C | 2.4°C | 221 mm | 78% | 5.1 m/s | 2.7 |
| 2016 | 17.1°C | 14.5°C | 11.9°C | 23.1°C | 7.6°C | 94 mm | 80% | 4.5 m/s | 2.7 |
| 2015 | 15.7°C | 13.1°C | 10.4°C | 21.4°C | 4.5°C | 45 mm | 75% | 5.4 m/s | 3 |
| 2014 | 14.5°C | 12.0°C | 9.4°C | 20.8°C | 4.0°C | 97 mm | 79% | 4.8 m/s | 2.8 |
| 2013 | 15.7°C | 12.7°C | 9.7°C | 24.0°C | 3.2°C | 107 mm | 78% | 4.6 m/s | 3 |
| 2012 | 14.3°C | 11.5°C | 8.8°C | 22.7°C | 4.1°C | 91 mm | 76% | 5.7 m/s | 2.9 |
| 2011 | 15.9°C | 12.9°C | 9.9°C | 23.0°C | 4.6°C | 75 mm | 76% | 4.5 m/s | 3.4 |
| 2010 | 17.1°C | 14.0°C | 10.9°C | 25.8°C | 3.0°C | 42 mm | 70% | 4.7 m/s | 3.6 |
| 2009 | 12.6°C | 10.2°C | 7.9°C | 17.4°C | 3.5°C | 192 mm | 81% | 5.2 m/s | 2.2 |
| 2008 | 14.9°C | 12.5°C | 10.1°C | 22.6°C | 3.5°C | 72 mm | 76% | 5.2 m/s | 3.1 |
| 2007 | 18.0°C | 15.0°C | 12.0°C | 26.2°C | 5.6°C | 72 mm | 78% | 5 m/s | 3 |
| 2006 | 13.3°C | 10.5°C | 7.7°C | 22.3°C | 2.5°C | 123 mm | 77% | 5.2 m/s | 3 |
| 2005 | 16.3°C | 13.9°C | 11.4°C | 25.6°C | 5.4°C | 33 mm | 76% | 4.4 m/s | 3 |
| 2004 | 15.9°C | 13.2°C | 10.5°C | 21.5°C | 3.5°C | 61 mm | 76% | 5 m/s | 2.9 |
| 2003 | 14.9°C | 11.8°C | 8.8°C | 22.9°C | 4.4°C | 55 mm | 73% | 4.3 m/s | 3.3 |
| 2002 | 13.1°C | 10.6°C | 8.0°C | 24.0°C | 2.7°C | 52 mm | 76% | 4.6 m/s | 2.9 |
| 2001 | 14.0°C | 11.2°C | 8.4°C | 21.9°C | 2.7°C | 202 mm | 79% | 5.4 m/s | 2.7 |
| 2000 | 16.6°C | 13.5°C | 10.3°C | 23.5°C | 4.8°C | 58 mm | 78% | 4.6 m/s | 3.2 |
| 1999 | 15.7°C | 12.4°C | 9.2°C | 21.2°C | 3.7°C | 38 mm | 72% | 5 m/s | 3.1 |
| 1998 | 16.6°C | 13.9°C | 11.1°C | 21.3°C | 6.4°C | 100 mm | 77% | 4.7 m/s | 3 |
| 1997 | 15.8°C | 12.8°C | 9.7°C | 25.5°C | 1.7°C | 58 mm | 73% | 5 m/s | 3.3 |
| 1996 | 14.8°C | 11.5°C | 8.3°C | 20.4°C | -0.5°C | 74 mm | 77% | 5.2 m/s | 3 |
| 1995 | 15.0°C | 11.7°C | 8.4°C | 21.9°C | 3.2°C | 106 mm | 77% | 5.2 m/s | 3.1 |
| 1994 | 15.1°C | 12.0°C | 8.9°C | 21.1°C | 3.6°C | 79 mm | 76% | 4.6 m/s | 3 |
| 1993 | 12.0°C | 8.9°C | 5.9°C | 19.4°C | 1.0°C | 70 mm | 81% | 4.8 m/s | 3.1 |
| 1992 | 13.5°C | 10.5°C | 7.4°C | 21.4°C | 0.7°C | 34 mm | 78% | 4.5 m/s | 3 |
| 1991 | 13.8°C | 10.8°C | 7.7°C | 19.7°C | 2.4°C | 208 mm | 79% | 5.1 m/s | 3 |
| 1990 | 14.1°C | 10.8°C | 7.6°C | 22.8°C | 2.9°C | 129 mm | 75% | 5.3 m/s | 3 |
| 1989 | 14.8°C | 11.6°C | 8.4°C | 20.7°C | 3.8°C | 45 mm | 77% | 5 m/s | 3.1 |
| 1988 | 11.7°C | 8.9°C | 6.0°C | 18.9°C | 0.1°C | 104 mm | 70% | 5.1 m/s | 3 |
| 1987 ❄️ | 12.0°C | 8.8°C | 5.6°C | 18.3°C | 2.2°C | 51 mm | 73% | 4.8 m/s | 3 |
| 1986 | 14.2°C | 11.5°C | 8.8°C | 20.1°C | 4.0°C | 69 mm | 84% | 4.4 m/s | 2.5 |
| 1985 | 13.9°C | 11.2°C | 8.5°C | 19.7°C | 5.9°C | 124 mm | 78% | 4.5 m/s | 2.8 |
| 1984 | 16.1°C | 13.1°C | 10.2°C | 20.2°C | 5.9°C | 88 mm | 79% | 4.2 m/s | 2.2 |
| 1983 | 14.4°C | 11.5°C | 8.6°C | 22.5°C | 2.1°C | 86 mm | 76% | 4.7 m/s | — |
| 1982 | 14.4°C | 10.8°C | 7.3°C | 21.6°C | 0.9°C | 57 mm | 74% | 4 m/s | — |
| 1981 | 13.2°C | 10.4°C | 7.6°C | 19.1°C | -1.0°C | 37 mm | 78% | 4.8 m/s | — |
Actual recorded October data for each year, 1981–2025 — sourced from NASA POWER.
The average high in October is around 15.1°C with lows near 9.3°C (mean 12.2°C), based on 45 years of NASA POWER data.
October averages 90 mm of rainfall in Chicago, about average for rainfall. The wettest on record was 221 mm in 2017.
The hottest October reached 28.4°C in 2025. The coldest dipped to -1°C in 1981.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average October temperatures have risen by about 3.2°C. Daytime highs moved from 14.4°C to 17.5°C and overnight lows from 8.4°C to 11.7°C over the same span.
October is one of the warmer months of the year in Chicago and about average for rainfall, so plan for around 15.1°C daytime highs and 9.3°C at night.
Not quite — October is the 8th coolest month in Chicago, averaging 12.2°C.
For October in Chicago, pack light layers you can adjust through the day, with typical highs of 15.1°C and lows of 9.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in October averages 76% — quite humid.
Average wind speed in October is 4.9 m/s. The windiest October on record averaged 5.7 m/s (2012).
The wettest October on record was 2017 with 221 mm. On average, October sees 90 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 Chicago behaves each October, 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 October specifically, along with year-by-year records and how the month has changed over the decades.
