Indianapolis in September
In September, Indianapolis averages 26°C (79°F) during the day and 16°C (61°F) at night, with around 8 days of rain (72 mm total).
ShoulderConditions are warm and beach-friendly. Occasional showers are likely but won't dominate.
It's peak hurricane season in Indianapolis during September. Travel is possible but expect storm risk, possible flight disruption, and generally lower travel insurance coverage.
How September compares to the rest of the year in Indianapolis
September is in the middle of the year for warmth in Indianapolis (4th of 12) and one of the driest months (11th of 12). Daytime temperature runs 9°C above the annual average (17°C). September runs 2°C cooler than August (28°C) and cools 7°C in October (19°C).
September sunrise & sunset in Indianapolis
Times shown for Indianapolis local time (America/Indiana/Indianapolis), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in Indianapolis — September
Golden-hour and blue-hour windows for the 15th of September, in Indianapolis's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Indianapolis in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (Shoulder) and Indianapolis's popularity.
Crowds & pricing — September in Indianapolis
Indianapolis is in a shoulder season month — fewer crowds, slightly lower prices, and a calmer atmosphere than peak weeks. Most major sights stay open with normal hours, though a handful of seasonal restaurants or boat trips may run reduced schedules. Many regulars consider these months the best time to visit because you trade a small amount of weather reliability for a much more pleasant on-the-ground experience.
Why this tier: excellent tourism weather peak hazard season (1 active)
Sun & mosquito risk — September in Indianapolis
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Indianapolis in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 3°C / 38°F | -5°C / 23°F | 82 mm | 10 | — |
| February | 6°C / 42°F | -4°C / 24°F | 86 mm | 10 | — |
| March | 11°C / 52°F | 1°C / 33°F | 127 mm | 12 | — |
| April | 17°C / 63°F | 6°C / 43°F | 107 mm | 12 | — |
| May | 23°C / 73°F | 13°C / 55°F | 124 mm | 14 | — |
| June | 28°C / 82°F | 18°C / 64°F | 102 mm | 12 | — |
| July | 29°C / 84°F | 20°C / 67°F | 115 mm | 13 | — |
| August | 28°C / 83°F | 19°C / 66°F | 89 mm | 11 | — |
| September | 26°C / 79°F | 16°C / 61°F | 72 mm | 8 | — |
| October | 19°C / 66°F | 10°C / 50°F | 87 mm | 11 | — |
| November | 11°C / 51°F | 2°C / 36°F | 76 mm | 8 | — |
| December | 7°C / 44°F | -1°C / 30°F | 85 mm | 10 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for Indianapolis in September →
Frequently asked questions
How hot is Indianapolis in September?
In September, Indianapolis averages a high of 26°C (79°F) and a low of 16°C (61°F) — generally warm.
Does it rain a lot in Indianapolis in September?
September sees occasional rain in Indianapolis, with about 8 rainy days on average.
Is September a good time to visit Indianapolis?
September is warm. It suits travelers who are comfortable with warm weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Indianapolis in September?
Pack light layers for warm days and cooler evenings. See the full September packing list for Indianapolis for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.