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 storms build in late.
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 Midwest will dominate early, allowing temperatures to steadily rise through the end of the workweek.
In Indianapolis and across Marion, Hamilton, and Hendricks 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. In Illinois, Chicago and Cook County will see highs in the low to mid-80s, while inland areas including Champaign, Springfield, and Decatur climb into the upper 80s.
Along the I-65 and I-70 corridors, increasing southwest winds could gust between 25 and 35 mph at times, briefly accelerating vegetation drying before moisture returns. Early-period fire risk will give way to a more active setup.
The precipitation outlook shows a 40 to 50 percent chance of above-normal rainfall developing between April 18 and April 22. Thunderstorms are expected to increase in coverage, with the potential for heavy rainfall, gusty winds, and localized flooding, especially along and south of I-70.
Residents should stay hydrated during peak heat, secure loose outdoor items, and remain alert for rapidly changing weather late in the period. Drivers should be prepared for sudden downpours and reduced visibility.
The most consistent heat is expected through April 18, followed by increasing storm chances into early next week. Additional advisories are likely as this pattern shifts from dry heat to a more active storm setup.
