Historical weather data, all-time temperature records, and monthly climate averages for Lockport, IL. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5 in Lockport is a classic swing day — historically, highs have ranged from a balmy 77° (2005) all the way down to a brutal 19° low (2018). On average, expect a cool 56° high and 34° low, with a 39% shot at rain and a lingering 7% chance of snow. Spring is here, but it hasn't fully committed.
Lockport knows extremes. The thermometer has swung from a scorching 102° on July 24, 2005 to a bone-chilling -24° on January 16, 2009 — a 126-degree range that captures the full drama of northern Illinois. Add a single-day rainfall record of 4.9 inches and a 13.8-inch snowstorm on New Year's Day 1999, and you've got a town that keeps you on your toes year-round.
Summer is Lockport's sweet spot, with average highs peaking around 84–85° in mid-July before tapering off through fall. Winters are legitimately cold — January highs average just 31°, so plan accordingly. If you're trying to dodge rain, avoid early May, when the wettest stretch of the year typically rolls through.