Historical weather data, all-time temperature records, and monthly climate averages for Westchester, IL. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Westchester runs cool, with an average high of 54° and a low of 37° across 28 years of records. The date has seen a 49-degree swing in extremes — from a 76° scorcher in 2021 down to a 27° freeze in 2018. There's a coin-flip chance of rain today, but snow is essentially off the table.
Westchester earns its Midwest stripes with a punishing 126-degree spread between its all-time extremes — 104° in July 1999 and -22° in January 2019. A single October day in 2017 dropped 5.2 inches of rain, and a December storm in 2000 buried the town under 14.3 inches of snow.
Summer peaks mid-July with average highs of 86°, while mid-January bottoms out at a frigid 30°. If you're trying to dodge rain, avoid early May — the week of May 7–13 is the wettest of the year. The shoulder months of April and October offer mild temps in the 60s if you're looking for a comfortable window.