Naperville averages 16.8 days a year above 90°F, with May the wettest month at 4.79 in of normal rain. Across decades of records, Fridays are 7% rainier than the weekly average. The hottest day on record was 102°F on Jul 6, 2012; the coldest, −23°F on Jan 30, 2019. The single biggest 24-hour rain event recorded was 5.52 in on Apr 18, 2013.
Climate and Average Weather Year Round in Naperville
Year-round temperature
In Naperville, the warmest months are June through September, with average daily highs between 76°F and 84°F. The coldest stretch runs December through February, with highs between 32°F and 37°F and overnight lows reaching 15°F.
Rainfall through the year
Rainfall in Naperville averages 3.3 in per month over the long run. May is the wettest at 4.8 in, while February is the driest at 2.0 in.
Days at 90 °F or hotter
Naperville averages 16.8 days per year at 90 °F or hotter. The hottest year on record saw 45 such days (2012); the coolest just 1 (2008).
Precipitation this year
As of May 28, Naperville has received 14.8 in of precipitation this year — 1% above the long-term normal for this point in the year (14.7 in).