Historical weather data, all-time temperature records, and monthly climate averages for Collinsville, IL. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5th in Collinsville runs mild, with highs averaging 65° and lows around 39° across 28 years of records. The date has swung wildly though — from a scorching 82° in 2010 to a bitter 26° low back in 2002. Rain is possible (32% chance), but snow is off the table.
Collinsville earns its Midwest stripes with some serious extremes — 107° in June 2012 on one end, and a brutal -14° in January 2014 on the other. Summer storms can be equally dramatic: a single day in July 2022 dumped 7.23 inches of rain, and New Year's Day 2015 brought 9 inches of snow.
Summer is the headline here, with highs pushing 91° in mid-July and staying in the upper 80s through August. If you're cold-averse, avoid mid-January when average highs barely reach 39°. The wettest stretch runs late June into early July, averaging 1.41 inches per week — prime thunderstorm season.