Historical weather data, all-time temperature records, and monthly climate averages for Chatham, IL. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Chatham runs cool, with an average high of just 54° and a low of 37°—classic early spring fence-sitting. The date has swung hard in both directions: a balmy 76° in 2021 and a sharp 27° low in 2018. There's a 43% chance of rain today, so keep a jacket handy.
Chatham has seen some serious extremes over its 29-year record. The thermometer has climbed to a scorching 104° in July 1999 and bottomed out at a brutal -22° in January 2019—a 126-degree swing. A single October day in 2017 dumped 5.2 inches of rain, and a December 2000 storm buried the area under 14.3 inches of snow.
Summer is the clear sweet spot, with highs topping out around 85-86° in mid-July, while January and February are the ones to avoid if you're cold-averse—highs barely crack the low 30s. May is the wettest stretch of the year, averaging over an inch of precipitation in a single week, so spring travel plans should account for soggy conditions.