Historical weather data, all-time temperature records, and monthly climate averages for Westmont, IL. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Westmont sits right in the thick of spring's unpredictability — 97 years of records show an average high of just 53° with nearly a coin-flip chance of rain. The date has seen everything from a balmy 80° back in 1929 to a brutal 16° low in 1975, so don't put away the layers just yet.
Westmont's weather has real teeth on both ends of the thermometer — the mercury has soared to 107° in June 1934 and crashed to -25° in January 1985, a 132-degree spread that tells you this is classic Midwest extremes territory. Summer storms can be serious too, with a single day in July 1957 dumping over 6 inches of rain.
Summer is the sweet spot for Westmont, with mid-July highs averaging 85° and the warmest stretch running July 9–15. Winters are legitimately cold — January highs barely crack 32° and the coldest week averages just 31°. If you're trying to dodge the rain, note that mid-to-late July is the wettest period, averaging over an inch of precipitation per week.