Historical weather data, all-time temperature records, and monthly climate averages for Rockford, IL. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Rockford is a true transitional day — expect a high around 51° and a low that can still dip to freezing. The date has swung wildly over 75 years of records, from a bitter 9° in 1975 to a t-shirt-worthy 78° as recently as 2021. There's a 40% chance of rain today, but snow is nearly off the table at just 3%.
Rockford earns its Midwestern stripes with a staggering 136-degree swing between its all-time extremes — from 105° on July 7, 2012 to -31° on January 31, 2019. A single August day in 1987 dumped 5.7 inches of rain, while a late-November storm in 2018 buried the city under 11.7 inches of snow in 24 hours.
Summer is the sweet spot: the week of July 16–22 tops out at an average high of 85° and is both the warmest and wettest stretch of the year. Winter bites hard, with mid-January highs averaging just 27° — cold enough that January's 28° average high is the lowest of any month. If you're planning a visit, May through September offers the most comfortable window, with highs climbing from 71° to a peak of 84° in July.