Indianapolis, Indiana weather in August

Averages from 2021–2025 (155 days of record).

Average high: 84°F
Average low: 66°F
Rainy days: ~11 per month
Total precipitation: 2.9 in
Warmest recorded: 94°F
Coldest recorded: 51°F

Expect August days in Indianapolis, Indiana to top out around 84°F and cool to about 66°F overnight, with roughly 11 days of measurable rain across the month. In recent years August has ranged from 51°F to 94°F.

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Current Indianapolis, Indiana forecast → · Historical data by Open-Meteo (ERA5).