Historical weather data, all-time temperature records, and monthly climate averages for Vernon Hills, IL. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5th in Vernon Hills is classic spring-in-progress: expect a high near 54° and a low around 35°, with nearly a 4-in-10 chance of rain. The date has swung wildly over the years — from a balmy 76° in 2005 to a brutal 21° low in 2002 — so the jacket stays in the car, not the closet.
Vernon Hills plays weather extremes hard. The thermometer has soared to 104° in July 2012 and crashed to -21° in January 2019 — a 125-degree swing that tells you everything about Midwest seasonality. The wettest single day on record dumped 4.53 inches in June 2013.
If you're chasing warmth, aim for mid-July, when average highs peak at 85°; if you're avoiding cold, steer clear of mid-January, when highs struggle to reach 30°. Late June through early July is the wettest stretch of the year, averaging over an inch of precipitation per week. Spring and fall offer mild shoulder seasons, though temperatures can shift dramatically from one day to the next.