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Naperville, IL Weather by Month and Climate Averages
Monthly normals · Rain · Snow
Sunshine · Freeze dates · Records · Best time to visit
What is the weather like in Naperville, IL?
Naperville, IL gets 40.2 in of precipitation a year over about 125 rainy days. July is the warmest month (average high 84°F) and January the coldest (average low 14°F).
Humid continental climate
Naperville, IL has hot summers and cold winters. Daytime highs range from about 31°F in January to 84°F in July. May is usually the wettest month, and snow falls in winter. The most comfortable time to visit is typically September to October, when daytime highs sit near 70°F.
| Season | Months | Avg low | Avg high |
|---|---|---|---|
| Winter | Dec–Feb | 17° | 34° |
| Spring | Mar–May | 37° | 59° |
| Summer | Jun–Aug | 60° | 83° |
| Autumn | Sep–Nov | 41° | 63° |
How much rain does Naperville get?
Naperville gets 40.2 in of precipitation in an average year, spread over about 125 days with measurable rain. That is more rainy days than 82% of the US.
May is the wettest month, with 4.8 in. February is the driest, with 2.0 in. May has the most rainy days, about 14.
The longest dry spell in the last five years lasted 20 days, to September 19, 2024.
From September 2025 to August 2026 Naperville got 42.5 in of rain, against a normal of 40.2 in for those months. July 2026 had the most, with 7.5 in.
See where Naperville ranks: rainiest cities in the US, US cities with the most rainy days, rainiest cities in Illinois.
Does it snow in Naperville?
The snowiest winter on record is 1978–79, with 83.7 in.
The most recent measurable snow at the station fell on March 18, 2026.
From September 2025 to August 2026 the station measured 34.1 in of snow. January 2026 had the most, with 11.3 in.
See where Naperville ranks: snowiest cities in the US.
Naperville weather by month
Naperville weather in January
In January, Naperville averages a high of 31°F and a low of 14°F. It gets 2.2 in of precipitation over about 10 rainy days. Estimated sunshine is 24% of daylight hours, derived from ERA5 cloud cover. The January record high is 64°F (2008) and the record low is -23°F (2019).
Naperville weather in February
In February, Naperville averages a high of 35°F and a low of 16°F. It gets 2.0 in of precipitation over about 9 rainy days. Estimated sunshine is 43% of daylight hours, derived from ERA5 cloud cover. The February record high is 74°F (2024) and the record low is -20°F (2019).
Naperville weather in March
In March, Naperville averages a high of 48°F and a low of 27°F. It gets 2.4 in of precipitation over about 9 rainy days. Estimated sunshine is 34% of daylight hours, derived from ERA5 cloud cover. The March record high is 86°F (2012) and the record low is -3°F (2014).
Naperville weather in April
In April, Naperville averages a high of 59°F and a low of 36°F. It gets 3.8 in of precipitation over about 12 rainy days. Estimated sunshine is 38% of daylight hours, derived from ERA5 cloud cover. The April record high is 86°F (2021) and the record low is 15°F (2013).
Naperville weather in May
In May, Naperville averages a high of 71°F and a low of 48°F. It gets 4.8 in of precipitation over about 14 rainy days. Estimated sunshine is 38% of daylight hours, derived from ERA5 cloud cover. The May record high is 97°F (2018) and the record low is 22°F (2013).
Naperville weather in June
In June, Naperville averages a high of 81°F and a low of 58°F. It gets 4.4 in of precipitation over about 13 rainy days. Estimated sunshine is 50% of daylight hours, derived from ERA5 cloud cover. The June record high is 99°F (2012) and the record low is 39°F (2015).
Naperville weather in July
In July, Naperville averages a high of 84°F and a low of 62°F. It gets 4.3 in of precipitation over about 10 rainy days. Estimated sunshine is 47% of daylight hours, derived from ERA5 cloud cover. The July record high is 102°F (2012) and the record low is 44°F (2009).
Naperville weather in August
In August, Naperville averages a high of 82°F and a low of 60°F. It gets 4.3 in of precipitation over about 10 rainy days. Estimated sunshine is 51% of daylight hours, derived from ERA5 cloud cover. The August record high is 97°F (2023) and the record low is 42°F (2009).
Naperville weather in September
In September, Naperville averages a high of 76°F and a low of 53°F. It gets 3.4 in of precipitation over about 9 rainy days. Estimated sunshine is 53% of daylight hours, derived from ERA5 cloud cover. The September record high is 95°F (2017) and the record low is 32°F (2012). September is one of the most comfortable months to visit.
Naperville weather in October
In October, Naperville averages a high of 63°F and a low of 41°F. It gets 3.6 in of precipitation over about 12 rainy days. Estimated sunshine is 50% of daylight hours, derived from ERA5 cloud cover. The October record high is 89°F (2025) and the record low is 23°F (2018). October is one of the most comfortable months to visit.
Naperville weather in November
In November, Naperville averages a high of 48°F and a low of 30°F. It gets 2.8 in of precipitation over about 8 rainy days. Estimated sunshine is 44% of daylight hours, derived from ERA5 cloud cover. The November record high is 77°F (2016) and the record low is 5°F (2014).
Naperville weather in December
In December, Naperville averages a high of 36°F and a low of 20°F. It gets 2.3 in of precipitation over about 10 rainy days. Estimated sunshine is 31% of daylight hours, derived from ERA5 cloud cover. The December record high is 70°F (2012) and the record low is -10°F (2016).
Sunshine, humidity and wind in Naperville
September is the sunniest month in Naperville, with estimated sunshine of 53% of daylight hours from ERA5 cloud cover. January is the cloudiest, at 24%. The annual cloud-cover estimate is 42% of daylight hours; it is not a measurement of sunshine duration. Naperville is cloudier than 81% of the US.
Humidity peaks in January at 78% and is lowest in June at 59%.
Naperville has about 17 days a year above 90°F. Naperville is cooler than 66% of the US.
See where Naperville ranks: sunniest cities in the US, cloudiest cities in the US, hottest cities in the US.
First and last freeze in Naperville
The first fall freeze in Naperville typically comes around October 12, and the last spring freeze around April 30. That leaves a frost-free growing season of about 165 days.
Naperville weather records
These records cover LISLE - MORTON ARBORETUM during 2007–2026. Earlier records or other stations in the city may differ.
The hottest temperature on record at the Naperville station is 102°F, on July 6, 2012. The coldest is -23°F, on January 30, 2019.
The wettest day in the available station history brought 5.5 in of precipitation, on April 18, 2013.
The best time to visit Naperville
The most comfortable time to visit is typically September to October, when daytime highs sit near 70°F.
Winter (December–February) is cold, with average highs around 34°F and lows near 17°F. Snow is possible.
Spring (March–May) is mild, with average highs around 59°F and lows near 37°F.
Summer (June–August) is hot, with average highs around 83°F and lows near 60°F.
Autumn (September–November) is mild, with average highs around 63°F and lows near 41°F.
Monthly climate
| Month | Average low | Average high | Precip | Rain days | Humidity | Estimated sunshine | Record high | Record low |
|---|---|---|---|---|---|---|---|---|
| January | 14° | 31° | 2.2 in | 10 | 78% | 24% | 64° | -23° |
| February | 16° | 35° | 2.0 in | 9 | 67% | 43% | 74° | -20° |
| March | 27° | 48° | 2.4 in | 9 | 64% | 34% | 86° | -3° |
| April | 36° | 59° | 3.8 in | 12 | 60% | 38% | 86° | 15° |
| May | 48° | 71° | 4.8 in | 14 | 60% | 38% | 97° | 22° |
| June | 58° | 81° | 4.4 in | 13 | 59% | 50% | 99° | 39° |
| July | 62° | 84° | 4.3 in | 10 | 70% | 47% | 102° | 44° |
| August | 60° | 82° | 4.3 in | 10 | 71% | 51% | 97° | 42° |
| September | 53° | 76° | 3.4 in | 9 | 68% | 53% | 95° | 32° |
| October | 41° | 63° | 3.6 in | 12 | 65% | 50% | 89° | 23° |
| November | 30° | 48° | 2.8 in | 8 | 67% | 44% | 77° | 5° |
| December | 20° | 36° | 2.3 in | 10 | 73% | 31% | 70° | -10° |
Station: LISLE - MORTON ARBORETUM, 7 km from the city. Temperature normal baseline: 1991–2020, calculated from available NOAA GHCN-Daily observations. Available station history: 2007–2026; record values refer to this station and period, not the entire city’s history. Precipitation includes rain and the water equivalent of frozen precipitation; snowfall depth is shown separately when available. Sources and methods
From ERA5 reanalysis. Sunshine is estimated from cloud cover.
Naperville climate questions
How much rain does Naperville get?
Naperville gets 40.2 in of precipitation in an average year, over about 125 rainy days.
What is the wettest month in Naperville?
May is the wettest month in Naperville, with 4.8 in. February is the driest, with 2.0 in.
How many rainy days does Naperville have a year?
Naperville has about 125 days with measurable rain in an average year. May has the most, about 14.
What is the hottest month in Naperville?
July is the warmest month in Naperville, with an average high of 84°F.
What is the coldest month in Naperville?
January is the coldest month in Naperville, with an average low of 14°F.
What is the record high temperature in Naperville?
Within the available 2007–2026 station history, the record high at the Naperville station is 102°F, set on July 6, 2012. The record low is -23°F, on January 30, 2019.
What is the sunniest month in Naperville?
September is the sunniest month in Naperville, with estimated sunshine of 53% of daylight hours from ERA5 cloud cover. January is the cloudiest.
When is the first frost in Naperville?
The first fall freeze in Naperville typically comes around October 12. The last spring freeze is around April 30.
What is the best time to visit Naperville?
The most comfortable time to visit is typically September to October, when daytime highs sit near 70°F.