Indianapolis
Indiana, USA
Long-term weather forecast
Long-term weather forecast

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

Humidity

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

Rainfall

In Indianapolis, in September, during 12.2 rainfall days, 1.46" (37mm) of precipitation is typically accumulated. Throughout the year, there are 146.4 rainfall days, and 21.14" (537mm) of precipitation is accumulated.

Snowfall

In Indianapolis snow does not fall in May through October.

Daylight

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

Sunshine

In September, the average sunshine is 8.4h.

UV index

In Indianapolis, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from unprotected exposure to the Sun's UV rays for average individuals.
Note: The daily maximum UV index of 4 in September interpret into the following advice:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.

What is the temperature in September in Indianapolis?

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

What is the average humidity in September in Indianapolis?

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

How many days does it rain in September in Indianapolis?

In Indianapolis, Indiana, in September, during 12.2 rainfall days, 1.46" (37mm) of precipitation is typically accumulated.

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?

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

How many hours of sunshine does Indianapolis have in September?

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

How high is the UV index in September in Indianapolis?

In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate vulnerability from the exposure to the Sun's UV radiation.
Average temperature in September - Indianapolis, IN
  • Average high temperature in September: 24.4°C

The warmest month (with the highest average high temperature) is July (27.8°C).
The month with the lowest average high temperature is January (0.8°C).

  • Average low temperature in September: 14.6°C

The month with the highest average low temperature is July (19°C).
The coldest month (with the lowest average low temperature) is January (-6.1°C).

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: 37mm

The wettest month (with the highest rainfall) is May (68mm).
The driest month (with the lowest rainfall) is February (31mm).

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 lowest number of rainy days is February (6.8 days).

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

The month with the highest snowfall is December (58mm).
Months with the lowest snowfall are May, June, July, August, September and October (0mm).

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 lowest number of 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 shortest days is December (Average daylight: 9.4h).

  • Average sunshine in September: 8.4h

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

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).