May 15 | Climate Review and Weather Update

by Trent Ford, State Climatologist
ISWS PRI University of Illinois

Spring weather extended yet another week with average temperatures from the low 50s in northern Illinois to low 60s in southern Illinois, between 3 and 8 degrees below normal. While most places stayed above freezing overnight this week, we did wake up to temperatures in the 30s and heavy frost, including lows of 33 degrees in Dixon and in Rockford. The cooler start to May is quite a contrast to what ended up being the warmest April on record statewide last month.

Before Friday morning, precipitation was a bit harder to come by this week. 7-day totals ending Friday morning ranged from virtually nothing in northeast Illinois to just over 1.5 inches along the I-70 corridor. Following an exceptionally wet April, the last few weeks have been quite a bit drier in much of the state. Much of northern Illinois has had a top 5 driest first half of May on record, including the driest start to May since 1958 in Rockford. The cooler, drier weather has helped dry out some fields and allowed planting progress to resume after very wet conditions in April.

Looking ahead, this upcoming weekend is not one to plan a lot of outdoor activities, at least those in which one prefers to stay dry. High temperatures will reach into the 80s and even low 90s in a few places in southern Illinois this weekend and early next week, before a cold front drops us back into the 60s and 70s by week’s end. Rain and thunderstorms are expected to be off and on the entire weekend, so if you plan on watching the Sox sweep the Cubs on the South Side, make sure to bring umbrellas and ponchos. 7-day precipitation forecasts show between 1 and 2 inches for the entire state, marking at least a temporary end to our dry stretch.