Indianapolis Weather in September
September in Indianapolis typically sees daytime highs of 26°C (79°F) and nighttime lows of 14°C (57°F). Rainfall is also possible this month, so it's worth packing an umbrella.
Rainfall in Indianapolis in September
Based on our climate data of the past 30 years, about 10 days of rain are anticipated, with 85 mm (3.3 in) on average. The rain this month tends to fall in heavier spells rather than light drizzle. When it rains, showers can be significant.
Temperature in Indianapolis in September
September tends to be one of the perfect months in Indianapolis, with 26°C (79°F) in the afternoon and 14°C (57°F) overnight. This gives the month a fairly typical daily rhythm, with warmer afternoons and more comfortable nights. At 14°C (57°F) overnight, it can feel quite a bit cooler after dark. Worth packing something warmer for evenings, but the cooler temperatures are ideal for sleeping.
Sunshine in Indianapolis in September
Enjoy a sunny month with about 235 hours of sunshine, the clear skies make Indianapolis even more beautiful.Our weather planner can help you find worldwide destinations with pleasant weather during this period. August and September typically offer the best weather for Indianapolis.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Indianapolis's climate page.
Indianapolis Temperature in September
Min Temperature
14°C (57°F)
Max Temperature
26°C (79°F)
Chance of Rain
33%
Precipitation
85 mm (3.3 in)
Rainy days
10 days
Humidity
75%
Sunshine
235 hours
Percentage Sunshine
62%
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Indianapolis typically drop from around 28°C (82°F) at the start of September to approximately 23°C (73°F) by the end. Nights are pleasant, with lows typically ranging from 11°C (52°F) to 18°C (64°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Indianapolis in September
Browse day-by-day weather records for Indianapolis spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Indianapolis historical weather extremes in September
Based on 49 years of weather observations in Indianapolis between 1976 and 2025, these are the recorded extremes.
- Indianapolis recorded its highest September temperature of 37°C (99°F) on September 2, 2011.
- The lowest daytime temperature in September was 12°C (54°F), recorded on September 27, 1984.
- Nighttime temperatures dropped to 1°C (34°F) on September 30, 1993, marking the coldest September night on record.
Best Places in the United States of America in September
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in September →
perfect weather
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unpleasant
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What to Wear in Indianapolis in September
Warm weather calls for comfortable, breathable clothing in September. Cotton t-shirts, shorts, light dresses, and sandals are perfect. You might still want a light layer for evenings or air-conditioned places (for example buses). High rain levels are expected, so pack waterproof gear and an umbrella or poncho. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.What To Do in Indianapolis in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Indianapolis's climate page.
Temperature Rainfall Sunshine Humidity
See the full Indianapolis climate overview or explore weather in the United States of America.
