Dec 20 | Yearly Climate Review and Weather Outlook

This year has been very warm across Illinois, to the tune of 3 to 4 degrees above normal. Through the middle of December, 2024 has been the warmest year on record in Chicago, Peoria, and Carbondale, and a top 5 warmest year on record virtually everywhere else across the state. Ironically, it was July – the climatologically warmest month of the year – that had statewide average temperatures farthest below normal. The mid-summer cool down was welcome following a very warm and dry start to the growing season. But, it didn’t last long, as temperatures were persistently 3 to 5 degrees above normal throughout fall. December temperatures to date have been right within 1 degree of normal statewide, but will likely end above normal given the very mild forecast ahead. 

As is always the case, precipitation was variable across the state this year. April and the first half of May were wetter across much of southern Illinois and caused some delays in planting. The tap turned off in mid-May and stayed off through almost all of June, before timely July rains came to the state. Those rains were a bit too heavy in the Metro East area, where parts of Monroe, St. Clair, and Madison Counties received more than 14 inches of rain in July. The remnants of hurricane Helene added to these totals in early September, and then the rest of fall was pretty dry. Overall, most of the state will end the year within 2 inches of normal total precipitation. Parts of east central Illinois have been consistently drier, with 5 to 6 inches below normal precipitation, and areas of the Metro East will end 2024 with a top 10 wettest year on record. 

 Finally, the Climate Prediction Center released its newest monthly and seasonal outlooks yesterday. January is expected to be wetter than normal across the state, with equal chances of above and below normal temperatures. This likely means lots of variability, with shots of colder air to break up milder weather periods next month. The 3-month outlook from January through March shows a similar pattern, with even higher chances of wetter than normal conditions.