Indianapolis weather in September
Long-run climate averages for Indianapolis, IN in September, plus what the forecast models say for the days ahead.
In September, Indianapolis averages 76°F by day and 57°F at night. The wettest month is usually May.
September in Indianapolis averages a daytime high of 76°F and an overnight low of 57°F, which reads as warm for this part of the world. Across the whole year Indianapolis sees roughly 42 inches of precipitation.
Climate averages tell you what to pack. They do not tell you what next Tuesday looks like - for that, see the live Indianapolis forecast with every model compared and how much they currently agree.
Indianapolis weather by month
what to expect in Indianapolis through the year, 1991-2020 averagesHere is Indianapolis's typical weather in each month: the average daytime high and overnight low in °F, how each month feels, and the wettest month marked. Use it to plan any trip to Indianapolis by season.
Bottom line: over the last 30 days the European model has been the most accurate forecast for Indianapolis, scoring 98/100 on our CheckWeather Score, ahead of the American at 91. See the full US accuracy scoreboard for exactly how every model is tested.
Common questions
How warm is Indianapolis in September?
Is September a good time to visit Indianapolis?
Does it rain a lot in Indianapolis in September?
Climate averages from ERA5 reanalysis. Model accuracy re-scored over a rolling 30 days. Page updated .