September weather forecast and climate
Indianapolis, IN

The magnificent Monument Circle in Indianapolis, Indiana with the surrounding cityscape, and a perfect blue night sky
The magnificent Monument Circle in Indianapolis, Indiana with the surrounding cityscape, and a perfect blue night sky
September is a great time to visit Indianapolis at the beginning of the autumn with mild conditions. The average temperatures are in the comfortable range of 55.9°F (13.3°C) to 78.1°F (25.6°C) with a decrease in humidity compared to the summer.
The daylight lasts for 12 hours with ample sunshine close to 8 hours and a reduction in thunderstorm activity. Cool breezes blow during the evenings, and the rainfall limits to 8 days during the month, registering 3.1" (78.7mm).
September is a lovely time in Indianapolis with lesser crowds at the end of the summer vacations and moderate weather.

What is the temperature in September in Indianapolis?

In Indianapolis, in September, the average high-temperature is 77.5°F (25.3°C), and the average low-temperature is 56.1°F (13.4°C).

How much does it rain in Indianapolis in September?

In Indianapolis, during September, the rain falls for 8.1 days and regularly aggregates up to 3.1" (79.2mm) of precipitation.

Does it snow in Indianapolis in September?

In Indianapolis, Indiana, in September, it doesn't snow. In October, it regularly snows.
Average temperature in September - Indianapolis, IN
  • Average high temperature in September: 77.6°F

The warmest month (with the highest average high temperature) is July (85°F).
The month with the lowest average high temperature is January (35.6°F).

  • Average low temperature in September: 56.2°F

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).

Average humidity in September - Indianapolis, IN
  • Average humidity in September: 74.4%

The month with the highest relative humidity is December (78%).
The month with the lowest relative humidity is April (65.6%).

Average rainfall in September - Indianapolis, IN
  • Average rainfall in September: 3.1"

The wettest month (with the highest rainfall) is May (5.1").
The driest month (with the lowest rainfall) is February (2.3").

Average rainfall days in September - Indianapolis, IN
  • Average rainfall days in September: 8.1 days

The month with the highest number of rainy days is May (13.1 days).
The month with the lowest number of rainy days is September (8.1 days).

Average snowfall in September - Indianapolis, IN
  • Average snowfall in September: 0"

The month with the highest snowfall is January (8.6").
Months with the lowest snowfall are May, June, July, August and September (0").

Average snowfall days in September - Indianapolis, IN
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (7.5 days).
Months with the lowest number of snowfall days are May, June, July, August and September (0 days).

Average daylight in September / Average sunshine in September - Indianapolis, IN
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 15h).
The month with shortest days is December (Average daylight: 9.4h).

  • Average sunshine in September: 7.8h

The month with most sunshine is June (Average sunshine: 9.6h).
The month with least sunshine is December (Average sunshine: 3.3h).

Average UV index in September - Indianapolis, IN
  • Average UV index in September: 6

Months with the highest UV index are June and July (UV index 9).
Months with the lowest UV index are January, November and December (UV index 2).

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