Early autumn · Weather & things to do
Indianapolis in September
Indianapolis cools off: highs slip to 78°F (26°C), from 83°F in August, with lows of 56°F (13°C) and about 3.2 in (81 mm) of rain.
September opens the best stretch on our comfort score, at 89/100 (the top score of the year).
- Avg high
- 78°F (26°C)
- Avg low
- 56°F (13°C)
- Rain
- 3.2 in (81 mm)
- Humidity
- 72%
- Cloud cover
- 45%
- Daylight
- ~12 h 15 min
- Comfort score
- 89/100 · Great
What September feels like
Warm afternoons near 78°F (26°C) make long days outdoors easy.
Mornings start much cooler: lows average 56°F (13°C), about 12°C (22°F) below the afternoon high.
Showers are part of the month, adding up to about 3.2 in (81 mm).
Plan around September
September is one of Indianapolis's best months on the climate data.
- Last warm month for a while: October highs fall to 65°F.
- Opens the best-scoring stretch on our comfort score: September & October.
- Comfort improves from 78/100 in August to 89/100.
- September sits inside the May – Oct window our Indiana & Ohio City-Nature Loop recommends.
What to pack for September
- Light, breathable clotheshighs average 78°F
- A warm layer for eveningsnights drop to 56°F
- Packable rain jacket or umbrellaa shower or two is likely
- Comfortable walking shoesmost places below are best reached on foot or with short walks
What to do in Indianapolis in September
With conditions on your side, the picks below favor time outside.
Shapiro's Delicatessen
Family-run deli since 1905; cafeteria line for corned beef and pastrami.
Eiteljorg Museum
Museum of Native American and Western art in White River State Park.
Garage Food Hall
Food hall in Bottleworks' old Coca-Cola bottling garage with local vendors.
Soldiers' and Sailors' Monument
Monument Circle's 284-foot centerpiece; ride or climb to the observation deck.
Indianapolis Cultural Trail
8-mile protected bike and walking path linking downtown's cultural districts.
Why now September scores 89/100 for comfort, good conditions for being outside.
Nearby in September
- Broad Ripple in September~7 mi · highs 78°F, 3.2 in rain · similar daytime temperatures, about as wet
- Downtown Cincinnati in September~99 mi · highs 82°F, 3.2 in rain · 2°C (4°F) warmer by day, about as wet
- Louisville in September~107 mi · highs 82°F, 3.7 in rain · 2°C (4°F) warmer by day, about as wet
- Indiana Dunes in September~138 mi · highs 76°F, 3.1 in rain · 1°C (2°F) cooler by day, about as wet
These averages also cover Downtown Indianapolis.
NASA POWER 2001–2025 monthly averages on a ~50 km grid. Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Indianapolis in September: quick answers
Is September a good time to visit Indianapolis?
Yes. On the climate data it's one of the best months, scoring 89/100. Expect highs of 78°F (26°C) and 3.2 in (81 mm) of rain. September is inside the May – Oct window our Indiana & Ohio City-Nature Loop recommends.
How hot is Indianapolis in September?
Average highs are 78°F (26°C) and average lows 56°F (13°C), making it the 4th-warmest month by daytime highs.
Does it rain a lot in Indianapolis in September?
Some: about 3.2 in (81 mm) of rain falls across September on average, the 3rd-driest month of the year. The annual total is about 44.9 in (1141 mm).
What should I pack for Indianapolis in September?
Bring light, breathable clothes (highs average 78°F), a warm layer for evenings (nights drop to 56°F), packable rain jacket or umbrella (a shower or two is likely) and comfortable walking shoes (most places below are best reached on foot or with short walks).
More on Indianapolis
Routes in season in September
- Indiana & Ohio City-Nature Loop May – Oct
Planning Indianapolis in September?
Plan it together in TripsCircle: one itinerary, one shared packing list and costs split as you go.