Indianapolis, Indiana – Temperatures will climb into the upper 80s by Thursday afternoon, pushing near 90°F and bringing a summerlike stretch of heat across Illinois and Indiana before a shift toward stormier conditions.
According to the National Weather Service and NOAA’s Climate Prediction Center, both states are in a 70 to 80 percent probability zone for above-normal temperatures from April 16 through April 20. A broad heat dome across the central U.S. will suppress rainfall early, allowing temperatures to steadily rise through the late week.
In Indianapolis and across Marion, Hamilton, and Johnson counties, highs are expected to reach 86 to 89°F between 2 p.m. and 6 p.m., with overnight lows holding in the mid to upper 60s. Along the I-65 and I-70 corridors, dry air and increasing southwest winds will accelerate vegetation drying, raising wildfire risk in grassy and rural areas.
Chicago and northern Illinois will see highs in the low to mid-80s, slightly cooler near Lake Michigan, while central Illinois cities including Champaign and Springfield will reach the upper 80s. In Indiana, Fort Wayne and South Bend will trend slightly cooler in the mid-80s, while Evansville may briefly touch 90°F during peak heating.
The precipitation outlook shows a transition during this period, with near-normal to slightly below-normal rainfall early shifting to a 40 to 50 percent chance of above-normal precipitation between April 18 and April 22. A corridor of heavier rainfall may develop from Illinois into Indiana, especially along and south of I-70.
Residents should avoid outdoor burning, stay hydrated, and secure loose outdoor items as winds increase. Drivers should be alert for crosswinds on major interstates, especially I-65, I-69, and I-70.
The most consistent heat is expected through April 19, followed by increasing storm chances into early next week. Additional advisories are likely as the pattern shifts from dry heat to a more active storm setup.
