Historical weather data, all-time temperature records, and monthly climate averages for Marion, IL. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5 in Marion runs mild, with a typical high of 63° and low of 41° based on 123 years of records. There's about a 1-in-3 chance of rain today, though snow is nearly off the table at just 1%. The date's range tells quite a story — from a sweltering 85° in 1932 to a bitter 23° back in 1900.
Marion's weather has real teeth at both extremes — a scorching 113° in August 1930 and a brutal -25° in January 1977 represent a 138-degree swing in recorded history. On the wet side, a single day in June 2000 dumped 6.9 inches of rain, and a February 1979 snowstorm left 10 inches on the ground.
Summer is the main event in Marion, with highs peaking around 91° during the third week of July and staying in the upper 80s through August. January is the coldest stretch, with average highs barely cracking 42°. If you're watching your umbrella, mid-May is the wettest window of the year, averaging over an inch of precipitation in a single week.