Des Moines, Iowa – Temperatures will climb into the upper 80s by Thursday afternoon, bringing a summerlike stretch of heat across Iowa and Illinois before a transition to wetter, storm-driven 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 Midwest will dominate early, allowing temperatures to steadily rise through the end of the workweek.
In Des Moines and across Polk and Dallas counties, highs are expected to reach 85 to 88°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, slightly cooler near Lake Michigan, while inland cities like Peoria and Rockford push into the upper 80s.
Along the I-80 corridor from Omaha through Des Moines to the Quad Cities and into Chicago, increasing southwest winds could gust between 25 and 35 mph, briefly elevating fire risk before moisture returns.
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 in urban corridors and low-lying areas.
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 the pattern shifts from dry heat to a more active storm setup.
