January is one of the cooler months of the year in Naperville, with average highs near -2°C and lows around -10.7°C (mean -6.3°C). It is one of the drier months, averaging 45 mm of rainfall and 89% relative humidity across the period.
January is one of the cooler months of the year in Naperville. Across 45 years of records, the warmest January in Naperville was 2006 — when the month averaged 0.5°C — while the coldest was 1982 at -14°C. Typical January days reach -2°C with nights near -10.7°C. The long-term trend is warming, about 0.7°C per decade.
January is one of the drier months in Naperville, averaging 45 mm of rainfall. The wettest January on record was 2005 with 95 mm, while the driest was 1981 at 3 mm.
Relative humidity in Naperville during January averages 89%. The most humid January was 1988 at 96%, and the least humid was 2003 at 75%.
January receives about 1.7 kWh/m²/day of solar energy in Naperville. The sunniest Januarys were 1985 and 2025 at 2.1 kWh/m²/day, and the cloudiest was 2023 at 1.2.
Average wind speed in Naperville during January is 4.1 m/s. The windiest January was 2014 at 5.1 m/s, while the calmest was 2023 at 3.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -8.5°C | -6.5°C | -5.2°C | -6.2°C | -4.9°C | +3.6°C |
| Avg High | -3.7°C | -2.1°C | -1.1°C | -2.0°C | -1.0°C | +2.7°C |
| Avg Low | -13.3°C | -10.9°C | -9.3°C | -10.6°C | -8.8°C | +4.5°C |
| Avg Rain | 29 mm | 60 mm | 43 mm | 41 mm | 52 mm | +23 mm |
January temperatures in Naperville have risen by about 4.5°C between 1981–1985 and 2021–2025.
January has ranged from a record low of -39°C (1982) to a record high of 16.6°C (1997).
Rainfall in January is one of the drier months, averaging 45 mm, with a wettest year of 95 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.5°C per decade while lows rose 0.9°C per decade, narrowing the gap between day and night.
A quieter season to visit Naperville
If your dates are flexible, the more temperate months of August and July tend to be the most comfortable for visiting Naperville. That said, January — with days averaging -2°C and nights around -10.7°C (mean -6.3°C) and moderate rainfall (45 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | -2.3°C | -6.7°C | -11.2°C | 9.6°C | -23.1°C | 29 mm | 76% | 4.5 m/s | 2.1 |
| 2024 | -2.3°C | -5.4°C | -8.6°C | 5.5°C | -27.6°C | 86 mm | 93% | 3.6 m/s | 1.6 |
| 2023 | 1.6°C | -1.8°C | -5.1°C | 8.0°C | -21.8°C | 59 mm | 88% | 3.4 m/s | 1.2 |
| 2022 | -3.5°C | -8.3°C | -13.1°C | 4.3°C | -24.1°C | 17 mm | 85% | 4.3 m/s | 1.9 |
| 2021 | -0.4°C | -4.3°C | -8.1°C | 4.1°C | -17.5°C | 48 mm | 90% | 3.6 m/s | 1.7 |
| 2020 | 0.6°C | -3.1°C | -6.8°C | 6.9°C | -17.3°C | 74 mm | 91% | 3.8 m/s | 1.4 |
| 2019 | -3.5°C | -7.9°C | -12.4°C | 9.7°C | -38.4°C | 44 mm | 90% | 4 m/s | 1.6 |
| 2018 | -1.1°C | -5.3°C | -9.6°C | 12.8°C | -23.6°C | 36 mm | 85% | 4.5 m/s | 1.8 |
| 2017 | 0.5°C | -3.1°C | -6.7°C | 12.8°C | -20.0°C | 63 mm | 86% | 3.8 m/s | 1.4 |
| 2016 | -1.8°C | -6.1°C | -10.4°C | 5.5°C | -22.3°C | 20 mm | 90% | 3.7 m/s | 1.7 |
| 2015 | -2.1°C | -6.6°C | -11.2°C | 5.2°C | -25.8°C | 31 mm | 88% | 3.7 m/s | 1.7 |
| 2014 | -5.9°C | -11.3°C | -16.7°C | 4.8°C | -30.0°C | 50 mm | 89% | 5.1 m/s | 1.5 |
| 2013 | -0.2°C | -4.7°C | -9.2°C | 15.6°C | -20.4°C | 82 mm | 82% | 4.5 m/s | 1.9 |
| 2012 | 1.4°C | -2.8°C | -7.0°C | 9.4°C | -17.6°C | 38 mm | 86% | 4.2 m/s | 1.9 |
| 2011 | -3.3°C | -7.0°C | -10.8°C | 1.1°C | -23.8°C | 21 mm | 86% | 3.6 m/s | 1.6 |
| 2010 | -3.8°C | -7.7°C | -11.6°C | 5.2°C | -23.1°C | 24 mm | 93% | 3.8 m/s | 1.7 |
| 2009 | -5.2°C | -10.3°C | -15.4°C | 2.0°C | -31.9°C | 27 mm | 91% | 3.9 m/s | 1.9 |
| 2008 | -0.7°C | -5.5°C | -10.3°C | 15.9°C | -22.8°C | 59 mm | 88% | 4.7 m/s | 1.7 |
| 2007 | 0.3°C | -3.6°C | -7.6°C | 9.6°C | -18.4°C | 46 mm | 88% | 4.3 m/s | 1.7 |
| 2006 🔥 | 4.0°C | 0.5°C | -3.0°C | 11.0°C | -9.7°C | 69 mm | 87% | 4.1 m/s | 1.7 |
| 2005 🌧️ | -2.1°C | -5.9°C | -9.8°C | 8.8°C | -21.3°C | 95 mm | 89% | 3.8 m/s | 1.6 |
| 2004 | -3.4°C | -7.5°C | -11.6°C | 12.5°C | -23.1°C | 19 mm | 85% | 4.3 m/s | 1.6 |
| 2003 | -3.1°C | -7.1°C | -11.0°C | 9.4°C | -20.6°C | 11 mm | 75% | 4.3 m/s | 1.9 |
| 2002 | 2.4°C | -1.3°C | -5.1°C | 12.4°C | -15.1°C | 38 mm | 87% | 4.1 m/s | 2 |
| 2001 | -2.0°C | -6.3°C | -10.7°C | 2.6°C | -18.1°C | 33 mm | 96% | 3.5 m/s | 2 |
| 2000 | -1.1°C | -5.1°C | -9.0°C | 12.8°C | -19.9°C | 34 mm | 84% | 4.2 m/s | 1.9 |
| 1999 | -3.2°C | -7.6°C | -12.0°C | 5.7°C | -28.2°C | 93 mm | 94% | 4.1 m/s | 1.8 |
| 1998 | 0.7°C | -3.3°C | -7.3°C | 10.7°C | -22.0°C | 72 mm | 92% | 3.5 m/s | 2 |
| 1997 | -3.6°C | -8.0°C | -12.4°C | 16.6°C | -28.0°C | 51 mm | 89% | 4.5 m/s | 1.8 |
| 1996 | -2.0°C | -6.6°C | -11.2°C | 13.7°C | -28.7°C | 42 mm | 87% | 4.6 m/s | 1.6 |
| 1995 | -2.7°C | -6.3°C | -9.9°C | 3.6°C | -18.8°C | 77 mm | 91% | 3.9 m/s | 1.7 |
| 1994 | -6.3°C | -10.4°C | -14.6°C | 2.1°C | -31.1°C | 46 mm | 91% | 4 m/s | 1.8 |
| 1993 | -1.8°C | -6.7°C | -11.6°C | 5.1°C | -21.5°C | 78 mm | 92% | 3.9 m/s | 1.8 |
| 1992 | -0.2°C | -3.9°C | -7.6°C | 4.7°C | -23.9°C | 53 mm | 90% | 4 m/s | 1.5 |
| 1991 | -4.8°C | -10.2°C | -15.7°C | 0.7°C | -26.8°C | 31 mm | 95% | 4.1 m/s | 2 |
| 1990 | 3.0°C | -1.8°C | -6.5°C | 10.9°C | -14.7°C | 56 mm | 85% | 4.5 m/s | 1.7 |
| 1989 | 1.8°C | -3.0°C | -7.8°C | 14.0°C | -20.9°C | 20 mm | 88% | 4.5 m/s | 1.7 |
| 1988 | -6.1°C | -11.4°C | -16.7°C | 9.8°C | -33.7°C | 55 mm | 96% | 4.3 m/s | 1.6 |
| 1987 | -1.4°C | -5.2°C | -9.0°C | 5.3°C | -23.1°C | 36 mm | 89% | 3.7 m/s | 1.8 |
| 1986 | -3.0°C | -7.6°C | -12.3°C | 8.1°C | -28.4°C | 14 mm | 92% | 4.2 m/s | 1.7 |
| 1985 | -7.0°C | -12.7°C | -18.3°C | 0.2°C | -36.2°C | 30 mm | 95% | 4.5 m/s | 2.1 |
| 1984 | -5.8°C | -10.7°C | -15.7°C | 0.7°C | -35.1°C | 24 mm | 96% | 3.7 m/s | 1.7 |
| 1983 | -0.4°C | -4.0°C | -7.7°C | 3.8°C | -15.2°C | 15 mm | 88% | 4 m/s | — |
| 1982 ❄️ | -8.2°C | -14.0°C | -19.9°C | 0.9°C | -39.0°C | 61 mm | 95% | 4.7 m/s | — |
| 1981 | -3.0°C | -7.5°C | -12.1°C | 7.8°C | -25.2°C | 3 mm | 86% | 3.7 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around -2°C with lows near -10.7°C (mean -6.3°C), based on 45 years of NASA POWER data.
January averages 45 mm of rainfall in Naperville, one of the drier months. The wettest on record was 95 mm in 2005.
The hottest January reached 16.6°C in 1997. The coldest dipped to -39°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have risen by about 4.5°C. Daytime highs moved from -4.9°C to -1.4°C and overnight lows from -14.7°C to -9.2°C over the same span.
January is one of the cooler months of the year in Naperville and one of the drier months, so plan for around -2°C daytime highs and -10.7°C at night.
Yes — January is the coldest month of the year in Naperville, averaging -6.3°C.
For January in Naperville, pack warm layers and a jacket for chilly mornings, with typical highs of -2°C and lows of -10.7°C.
Relative humidity in January averages 89% — quite humid.
Average wind speed in January is 4.1 m/s. The windiest January on record averaged 5.1 m/s (2014).
The wettest January on record was 2005 with 95 mm. On average, January sees 45 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 Naperville behaves each January, 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 January specifically, along with year-by-year records and how the month has changed over the decades.
