Indiana Weather Alert: Heat Index Over 100°F and Thunderstorms to Impact Central Indiana

Indianapolis, IN – July 21, 2025 — Central Indiana is gearing up for a week of intense summer heat and scattered thunderstorms, beginning Tuesday, July 22. The National Weather Service (NWS) warns that temperatures will climb above 90°F, and heat index values could top 100°F by Wednesday, raising health concerns across the region.

Storms Possible Tuesday Afternoon

Scattered thunderstorms are expected to develop later today, especially southwest of Interstate 74, including parts of Indianapolis and surrounding counties. While storms are not forecast to be severe, brief downpours and lightning could disrupt outdoor plans.

Key Reminders for Tuesday:

• Monitor skies and radar for storm development
• Avoid outdoor events during downpours or lightning
• Roads may become slick during isolated showers

Heat Wave Intensifies Midweek

Starting Wednesday, July 23, daytime highs will rise into the low 90s, but it will feel even hotter due to high humidity. The heat index — or “feels like” temperature — could surpass 100°F, prompting concern for heat exhaustion and dehydration.

Tips to Stay Safe:

• Stay indoors during peak heat hours (noon to 6 p.m.)
• Drink water regularly, even if you’re not thirsty
• Use fans or air conditioning, and check on elderly neighbors

Unsettled Weekend Ahead

The heat will continue through Thursday, with only a slight chance of afternoon storms (20%). Friday brings a higher chance of thunderstorms, especially in the afternoon and evening.

Looking to the weekend, Indianapolis can expect a 60% chance of rain and storms on both Saturday and Sunday, along with temperatures ranging from the mid-80s to low 90s. Rainfall may bring brief relief from the heat, but humidity will remain high.

5-Day Forecast for Indianapolis