Indianapolis/ Weather & Environment

Circle City Wakes in Fog, Boils by Tuesday as Heat Index Nears 100

AI Assisted Icon
Published on September 13, 2026
Circle City Wakes in Fog, Boils by Tuesday as Heat Index Nears 100Source: Google Street View

Indianapolis woke Sunday to fog and mist, with temperatures near 70 degrees and calm winds around sunrise. The fog should lift after 9 a.m., making way for mostly sunny skies and a warm afternoon. Drivers heading out early should slow down and use low-beam headlights where visibility is changing quickly.

Fog Clears Before A Late-Day Storm Chance

Temperatures are expected to climb into the mid-80s, with a high near 85 before easing toward the low 80s later in the afternoon. Isolated showers and thunderstorms could develop late Sunday afternoon and early evening, but the chance of precipitation is only about 20%. Northwest winds will run 1 to 9 mph and may become breezier later in the day, according to the National Weather Service Indianapolis.

Monday Brings A Short Cooldown

Sunday night should turn partly cloudy after a few isolated showers or storms fade before 9 p.m. The low will settle near 58 degrees, with north-northeast winds at 6 to 10 mph and temperatures edging upward overnight. Monday looks noticeably cooler and drier, with sunny skies, an afternoon high near 77 and an east-northeast wind around 8 mph.

Heat Returns Tuesday With Storms Building Midweek

The cooldown will be brief, as sunshine and a south wind push Indianapolis to around 92 degrees Tuesday. Tuesday night brings a 50% chance of showers and thunderstorms, followed by additional storm chances Wednesday and Thursday as highs remain near 90. Heat-index values could reach the upper 90s to low 100s during the hottest stretch.

Showers Stay Possible Into Next Weekend

Rain and thunderstorm chances remain in the forecast Wednesday night and Thursday night, while Friday and Saturday bring chances for rain showers with highs near 85 and 81. Overnight lows should generally remain in the 60s and lower 70s before cooler air arrives later in the week. For now, the best outdoor window is Monday, with the steamiest conditions returning Tuesday through Thursday.