September weather forecast
Fairfield, MT

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Weather in September

September, the first month of the autumn in Fairfield, is still a pleasant month, with temperature in the range of an average high of 68.2°F (20.1°C) and an average low of 48.6°F (9.2°C).

Temperature

Onset of September comes with a temperature decline, the average high falling from a moderately hot 79°F (26.1°C) in August to an agreeable 68.2°F (20.1°C). In September, Fairfield encounters an average low-temperature of 48.6°F (9.2°C) during the night.

Humidity

The average relative humidity in September in Fairfield is 48%.

Rainfall

In September, the rain falls for 6.1 days. Throughout September, 0.79" (20mm) of precipitation is accumulated. In Fairfield, during the entire year, the rain falls for 73.3 days and collects up to 9.17" (233mm) of precipitation.

Snowfall

January through May, September through December are months with snowfall. September is the first month it typically snows in Fairfield. Throughout September, in the average 0.7 snowfall days, it receives 0.55" (14mm) of snow. In Fairfield, Montana, during the entire year, snow falls for 50.3 days and aggregates up to 21.26" (540mm) of snow.

Daylight

In Fairfield, Montana, the average length of the day in September is 12h and 33min.
On the first day of the month, sunrise is at 6:47 am and sunset at 8:07 pm. On the last day of September, sunrise is at 7:26 am and sunset at 7:08 pm MDT.

Sunshine

In Fairfield, the average sunshine in September is 9.7h.

UV index

In Fairfield, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for average individuals.
Note: A maximum daily UV index of 4 during September morphs into the following directions:
Exercise prevention - Precautions against solar damage are endorsed. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Take note! UV radiation from the Sun can double in intensity due to snow reflection.
Updated: Feb 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Fairfield in September?

During September, Fairfield experiences an average high-temperature of 68.2°F (20.1°C) and a low-temperature of 48.6°F (9.2°C).

What is the average humidity in September in Fairfield?

In September, the average relative humidity in Fairfield, Montana, is 48%.

How many days does it rain in September in Fairfield?

In September, the rain falls for 6.1 days. Throughout September, 0.79" (20mm) of precipitation is accumulated.

When does it start snowing in Fairfield?

September is the first month it typically snows in Fairfield. Throughout September, in the average 0.7 snowfall days, it receives 0.55" (14mm) of snow.

How many hours of daylight does Fairfield have in September?

The average day length in September in Fairfield, Montana, is 12h and 33min.

When is the sunrise / sunset in September in Fairfield?

In September, on the first day of the month, sunrise is at 6:47 am and sunset at 8:07 pm. On the last day of the month, in Fairfield, sunrise is at 7:26 am and sunset at 7:08 pm MDT.

How long on average sun shines in September in Fairfield?

The average sunshine duration in September in Fairfield, Montana, is 9.7h.

What is the UV index reading in September in Fairfield?

In Fairfield, Montana, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Fairfield, MT

Average temperature in September - Fairfield, MT
  • Average high temperature in September: 68.2°F

The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is December (28.8°F).

  • Average low temperature in September: 48.6°F

The month with the highest average low temperature is August (55.9°F).
The coldest month (with the lowest average low temperature) is December (16.2°F).

Average pressure in September
Fairfield, MT

Average pressure in September - Fairfield, MT
  • Average pressure in September: 29.96"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

Average wind speed in September
Fairfield, MT

Average wind speed in September - Fairfield, MT
  • Average wind speed in September: 8.8mph

The windiest month (with the highest average wind speed) is January (11.2mph).
The calmest months (with the lowest average wind speed) are July and August (8mph).

Average humidity in September
Fairfield, MT

Average humidity in September - Fairfield, MT
  • Average humidity in September: 48%

The month with the highest relative humidity is January (76%).
The month with the lowest relative humidity is August (42%).

Average rainfall in September
Fairfield, MT

Average rainfall in September - Fairfield, MT
  • Average rainfall in September: 0.79"

The wettest month (with the highest rainfall) is June (1.93").
The driest month (with the least rainfall) is December (0.35").

Average rainfall days in September
Fairfield, MT

Average rainfall days in September - Fairfield, MT
  • Average rainfall days in September: 6.1 days

The month with the highest number of rainy days is May (11.3 days).
The month with the least rainy days is November (2.7 days).

Average snowfall in September
Fairfield, MT

Average snowfall in September - Fairfield, MT
  • Average snowfall in September: 0.55"

The month with the highest snowfall is February (4.17").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
Fairfield, MT

Average snowfall days in September - Fairfield, MT
  • Average snowfall days in September: 0.7 days

The month with the highest number of snowfall days is February (11.3 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in September /
Average sunshine in September
Fairfield, MT

Average daylight in September / Average sunshine in September - Fairfield, MT
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

Average sunshine days in September
Fairfield, MT

Average sunshine days in September - Fairfield, MT
  • Average sunshine days in September: 21 days

The month with the most sunshine days is October (23.2 days).
The month with the least sunshine days is February (15.8 days).

Average UV index in September
Fairfield, MT

Average UV index in September - Fairfield, MT
  • Average UV index in September: 4

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

Average cloud cover in September
Fairfield, MT

Average cloud cover in September - Fairfield, MT
  • Average cloud cover in September: 22

The month with the most cloud cover is February (Cloud cover 41).
The month with the least cloud cover is July (Cloud cover 14).

Average visibility in September
Fairfield, MT

Average visibility in September - Fairfield, MT
  • Average visibility in September: 6mi

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

Fairfield, Montana, USA

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