Indianapolis weather in September
September is one of the best months to visit Indianapolis: highs of 25°C (78°F) and about 81 mm (3.2 in) of rain on average. Nights average 13°C (56°F) and cloud cover 45% (NASA POWER, 2001–2025 averages). It is the 3rd driest month of the year and the 4th warmest. Compared with August, it is cooler and about as wet; October brings highs of 18°C (64°F) and 93 mm (3.7 in) of rain.
Is September a good time to visit Indianapolis?
best month Weather score 78/100.
Yes. September is one of the best months for weather in Indianapolis.
Does it rain a lot in Indianapolis in September?
Some rain is normal: about 81 mm (3.2 in) falls in an average September. It is the 3rd driest month of the year.
How warm is Indianapolis in September?
Days average 25°C (78°F) and nights 13°C (56°F).
Indianapolis weather by month
| Month | High | Low | Rain | Cloud | Weather |
|---|---|---|---|---|---|
| January | 1°C (34°F) | -7°C (19°F) | 75 mm | 71% | least pleasant |
| February | 3°C (38°F) | -6°C (21°F) | 68 mm | 70% | least pleasant |
| March | 10°C (49°F) | -1°C (30°F) | 88 mm | 66% | least pleasant |
| April | 17°C (63°F) | 5°C (41°F) | 111 mm | 61% | fair |
| May | 22°C (72°F) | 11°C (52°F) | 119 mm | 62% | best |
| June | 27°C (80°F) | 17°C (62°F) | 134 mm | 53% | best |
| July | 28°C (83°F) | 18°C (65°F) | 112 mm | 50% | best |
| August | 28°C (83°F) | 17°C (63°F) | 95 mm | 48% | best |
| September | 25°C (78°F) | 13°C (56°F) | 81 mm | 45% | best |
| October | 18°C (64°F) | 6°C (43°F) | 93 mm | 55% | best |
| November | 10°C (50°F) | 0°C (32°F) | 82 mm | 60% | least pleasant |
| December | 4°C (38°F) | -4°C (24°F) | 83 mm | 72% | least pleasant |
Sources: 2001–2025 monthly averages from NASA POWER (MERRA-2 reanalysis). Page updated . How we rate months