September weather forecast
Fairfax, IN

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Weather in September

September, the first month of the autumn in Fairfax, is still a warm month, with temperature in the range of an average low of 55.4°F (13°C) and an average high of 73.9°F (23.3°C).

Temperature

With the beginning of September, the average high-temperature shows a small decrease, transitioning from 79.3°F (26.3°C) in August to a still warm 73.9°F (23.3°C). The low-temperature in Fairfax averages to a moderate 55.4°F (13°C) during the nights of September.

Humidity

In Fairfax, the average relative humidity in September is 79%.

Rainfall

In Fairfax, in September, during 12.9 rainfall days, 1.54" (39mm) of precipitation is typically accumulated. Throughout the year, there are 151.9 rainfall days, and 23.39" (594mm) of precipitation is accumulated.

Snowfall

In Fairfax, snow does not fall in June through September.

Daylight

The average length of the day in September is 12h and 27min.
On the first day of the month, sunrise is at 7:07 am and sunset at 8:12 pm. On the last day of September, in Fairfax, sunrise is at 7:36 am and sunset at 7:23 pm EDT.

Sunshine

In Fairfax, Indiana, the average sunshine in September is 7.9h.

UV index

The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for the average person.
Note: A maximum UV index of 4 in September translates into the following recommendations:
Put precautions into practice - Protective measures against sun-induced damage are advised. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Updated: Aug 20, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

In Fairfax, 73.9°F (23.3°C) is the average high-temperature and 55.4°F (13°C) is the average low-temperature during September. In July, the average heat index (a.k.a. 'real feel', 'feels like'), which represents the influence of relative humidity on air temperature, is calculated to be 86°F (30°C).

What is the average humidity in September?

In September, the average relative humidity is 79%.

How many days does it rain in September?

In Fairfax, in September, during 12.9 rainfall days, 1.54" (39mm) of precipitation is typically accumulated.

When it does not snow?

June through September are months without snowfall in Fairfax.

Does it snow in September?

In Fairfax, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September?

In Fairfax, the average day length in September is 12h and 27min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 7:07 am and sunset at 8:12 pm. On the last day of the month, sunrise is at 7:36 am and sunset at 7:23 pm EDT.

How long on average sun shines in September?

The average sunshine duration in September is 7.9h.

What is the UV index intensity in September?

In Fairfax, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Fairfax, IN

Average temperature in September - Fairfax, IN
  • Average high temperature in September: 73.9°F

The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (30.7°F).

  • Average low temperature in September: 55.4°F

The month with the highest average low temperature is July (63.9°F).
The coldest month (with the lowest average low temperature) is January (19.2°F).

Average pressure in September
Fairfax, IN

Average pressure in September - Fairfax, IN
  • Average pressure in September: 30.04"Hg

The months with the highest atmospheric pressure are January and November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in September
Fairfax, IN

Average wind speed in September - Fairfax, IN
  • Average wind speed in September: 6.9mph

The windiest month (with the highest average wind speed) is January (10.5mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).

Average humidity in September
Fairfax, IN

Average humidity in September - Fairfax, IN
  • Average humidity in September: 79%

The months with the highest relative humidity are January and February (84%).
The month with the lowest relative humidity is October (75%).

Average rainfall in September
Fairfax, IN

Average rainfall in September - Fairfax, IN
  • Average rainfall in September: 1.54"

The wettest month (with the highest rainfall) is April (2.95").
The driest month (with the least rainfall) is February (1.38").

Average rainfall days in September
Fairfax, IN

Average rainfall days in September - Fairfax, IN
  • Average rainfall days in September: 12.9 days

The month with the highest number of rainy days is May (17.8 days).
The month with the least rainy days is February (6.8 days).

Average snowfall in September
Fairfax, IN

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

The month with the highest snowfall is February (3.58").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Fairfax, IN

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

The month with the highest number of snowfall days is January (13.3 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Fairfax, IN

Average daylight in September / Average sunshine in September - Fairfax, IN
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in September: 7h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 18min).

Average sunshine days in September
Fairfax, IN

Average sunshine days in September - Fairfax, IN
  • Average sunshine days in September: 15 days

The month with the most sunshine days is November (16.1 days).
The month with the least sunshine days is February (10.4 days).

Average UV index in September
Fairfax, IN

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

The month with the highest UV index is June (UV index 6).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in September
Fairfax, IN

Average cloud cover in September - Fairfax, IN
  • Average cloud cover in September: 36

The month with the most cloud cover is January (Cloud cover 66).
The months with the least cloud cover are July and August (Cloud cover 33).

Average visibility in September
Fairfax, IN

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

The months with the highest visibility are February, March, April, May, June, July, September, October, November and December (6mi).
The months with the lowest visibility are January and August (5mi).

Fairfax, Indiana, USA

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