September weather forecast and climate
Indianapolis, IN

The magnificent Monument Circle in Indianapolis, Indiana with the surrounding cityscape
The magnificent Monument Circle in Indianapolis, Indiana with the surrounding cityscape
The first month of the autumn, September, is still a warm month in Indianapolis, Indiana, with average temperature fluctuating between 75.9°F (24.4°C) and 58.3°F (14.6°C).

Temperature

In Indianapolis, the average high-temperature is almost the same as in August - a still moderately hot 75.9°F (24.4°C). In Indianapolis, the average low-temperature is 58.3°F (14.6°C).

Humidity

In Indianapolis, the average relative humidity is 76%.

Rainfall

In September, the rain falls for 12.2 days. Throughout September, 1.46" (37mm) of precipitation is accumulated. In Indianapolis, during the entire year, the rain falls for 146.4 days and collects up to 21.14" (537mm) of precipitation.

Snowfall

May through October are months without snowfall in Indianapolis.

Daylight

In September, the average length of the day is 12.4h.

Sunshine

In September, the average sunshine in Indianapolis is 8.4h.

UV index

The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to the Sun's UV rays for ordinary individuals.
Note: The average daily UV index of 4 transform into the following instructions:
Take precautions - Protection against the skin and eye damage is obliged. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.

What is the temperature in September in Indianapolis?

In Indianapolis, in September, the average high-temperature is 75.9°F (24.4°C), and the average low-temperature is 58.3°F (14.6°C).

What is the average humidity in September in Indianapolis?

In Indianapolis, Indiana, the average relative humidity in September is 76%.

How much does it rain in Indianapolis in September?

In Indianapolis, in September, it is raining for 12.2 days, with typically 1.46" (37mm) of accumulated precipitation.

When it does not snow in Indianapolis?

In Indianapolis snow does not fall in May through October.

What is the average length of the day in September in Indianapolis?

The average length of the day in September in Indianapolis is 12.4h.

How long on average sun shines in September in Indianapolis?

In September, the average sunshine is 8.4h.

What is the UV index intensity in September in Indianapolis?

The average daily maximum UV index in September in Indianapolis, Indiana, is 4. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from unprotected exposure to the UV radiation.
Average temperature in September - Indianapolis, IN
  • Average high temperature in September: 75.9°F

The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (33.4°F).

  • Average low temperature in September: 58.3°F

The month with the highest average low temperature is July (66.2°F).
The coldest month (with the lowest average low temperature) is January (21°F).

Average pressure in September - Indianapolis, IN
  • Average pressure in September: 30.03"

The month with the highest atmospheric pressure is January (30.14").
The month with the lowest atmospheric pressure is June (29.93").

Average wind speed in September - Indianapolis, IN
  • Average wind speed in September: 6.5mph

The windiest months (with the highest average wind speed) are January and February (9.8mph).
The calmest month (with the lowest average wind speed) is August (5.7mph).

Average humidity in September - Indianapolis, IN
  • Average humidity in September: 76%

The month with the highest relative humidity is December (82%).
The month with the lowest relative humidity is October (73%).

Average rainfall in September - Indianapolis, IN
  • Average rainfall in September: 1.46"

The wettest month (with the highest rainfall) is May (2.68").
The driest month (with the least rainfall) is February (1.22").

Average rainfall days in September - Indianapolis, IN
  • Average rainfall days in September: 12.2 days

The month with the highest number of rainy days is May (17.6 days).
The month with the least rainy days is February (6.8 days).

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

The month with the highest snowfall is December (2.28").
Months with the least snowfall are May, June, July, August, September and October (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 (7.9 days).
Months with the least snowfall days are 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 the shortest days is December (Average daylight: 9.4h).

  • Average sunshine in September: 8.4h

The month with the most sunshine is July (Average sunshine: 10.3h).
The month with the least sunshine is January (Average sunshine: 4.1h).

Average sunshine days in September - Indianapolis, IN
  • Average sunshine days in September: 15.2 days

The month with the most sunshine days is October (18.6 days).
The month with the least sunshine days is May (11.1 days).

Average UV index in September - Indianapolis, IN
  • Average UV index in September: 4

Months with the highest UV index are May, June, July and August (UV index 6).
Months with the lowest UV index are January, February, October, November and December (UV index 2).

Average cloud cover in September - Indianapolis, IN
  • Average cloud cover in September: 32

The month with the most cloud cover is January (Cloud cover 59).
The month with the least cloud cover is August (Cloud cover 29).

Average visibility in September - Indianapolis, IN
  • Average visibility in September: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).