September weather forecast
Fishtail, MT

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Weather in September

September, the first month of the autumn in Fishtail, is still a pleasant month, with an average temperature fluctuating between 72°F (22.2°C) and 50.2°F (10.1°C).

Temperature

September brings a decrease in the average high-temperature, falling from August's moderately hot 81.1°F (27.3°C) to an agreeable 72°F (22.2°C). Despite a significant daily temperature range, Fishtail's temperature falls to a steady low-temperature average of 50.2°F (10.1°C) in September.

Humidity

In Fishtail, the average relative humidity in September is 45%.

Rainfall

In Fishtail, during September, the rain falls for 6.9 days and regularly aggregates up to 0.79" (20mm) of precipitation. Throughout the year, there are 108.1 rainfall days, and 12.83" (326mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Fishtail are January through June, September through December. September is the first month it typically snows in Fishtail. Throughout September, in the average 0.8 snowfall days, it receives 0.67" (17mm) of snow. Throughout the year, there are 61.5 snowfall days, and 41.77" (1061mm) of snow is accumulated.

Daylight

In September, the average length of the day is 12h and 31min.
On the first day of September, sunrise is at 6:40 am and sunset at 7:55 pm. On the last day of the month, sunrise is at 7:15 am and sunset at 6:59 pm MDT.

Sunshine

The average sunshine in September in Fishtail is 10.6h.

UV index

In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for the average person.
Note: The average daily UV index of 4 in September transforms into the following instructions:
Exercise prevention - Warding off sunburn is urged. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Be informed! The Sun's UV radiation can be nearly doubled due to the reflection from snow.
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 Fishtail in September?

During September, Fishtail experiences an average high-temperature of 72°F (22.2°C) and a low-temperature of 50.2°F (10.1°C). The average heat index (a.k.a. 'real feel', 'felt air temperature'), which combines relative humidity and air temperature, in August is computed to be 80.6°F (27°C).

What is the average humidity in September in Fishtail?

In September, the average relative humidity is 45%.

How much does it rain in Fishtail in September?

In Fishtail, during September, the rain falls for 6.9 days and regularly aggregates up to 0.79" (20mm) of precipitation.

When does it start to snow in Fishtail?

September is the first month it typically snows in Fishtail, Montana. Throughout September, in the average 0.8 snowfall days, it receives 0.67" (17mm) of snow.

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

In Fishtail, Montana, the average day length in September is 12h and 31min.

When is the sunrise / sunset in September in Fishtail?

On the first day of September, sunrise is at 6:40 am and sunset at 7:55 pm. On the last day of the month, sunrise is at 7:15 am and sunset at 6:59 pm MDT.

How long on average sun shines in September in Fishtail?

In Fishtail, Montana, the average sunshine duration in September is 10.6h.

How high is the UV index in September in Fishtail?

The average daily maximum UV index in September in Fishtail, Montana, is 4. A UV Index reading of 3 to 5 represents 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
Fishtail, MT

Average temperature in September - Fishtail, MT
  • Average high temperature in September: 72°F

The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is December (30.7°F).

  • Average low temperature in September: 50.2°F

The months with the highest average low temperature are July and August (57.2°F).
The coldest month (with the lowest average low temperature) is February (16.7°F).

Average pressure in September
Fishtail, MT

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

The months with the highest atmospheric pressure are January and December (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

Average wind speed in September
Fishtail, MT

Average wind speed in September - Fishtail, MT
  • Average wind speed in September: 6.9mph

The windiest month (with the highest average wind speed) is January (8.7mph).
The calmest month (with the lowest average wind speed) is August (6mph).

Average humidity in September
Fishtail, MT

Average humidity in September - Fishtail, MT
  • Average humidity in September: 45%

The month with the highest relative humidity is January (76%).
The month with the lowest relative humidity is August (41%).

Average rainfall in September
Fishtail, MT

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

The wettest month (with the highest rainfall) is May (2.09").
The driest month (with the least rainfall) is January (0.51").

Average rainfall days in September
Fishtail, MT

Average rainfall days in September - Fishtail, MT
  • Average rainfall days in September: 6.9 days

The month with the highest number of rainy days is May (16.3 days).
The month with the least rainy days is February (4 days).

Average snowfall in September
Fishtail, MT

Average snowfall in September - Fishtail, MT
  • Average snowfall in September: 0.67"

The month with the highest snowfall is February (6.81").
The months with the least snowfall are July and August (0").

Average snowfall days in September
Fishtail, MT

Average snowfall days in September - Fishtail, MT
  • Average snowfall days in September: 0.8 days

The month with the highest number of snowfall days is February (10.8 days).
The months with the least snowfall days are July and August (0 days).

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

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

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in September: 10h and 4min

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 6h and 12min).

Average sunshine days in September
Fishtail, MT

Average sunshine days in September - Fishtail, MT
  • Average sunshine days in September: 18.4 days

The month with the most sunshine days is December (19.7 days).
The month with the least sunshine days is May (10.5 days).

Average UV index in September
Fishtail, MT

Average UV index in September - Fishtail, 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, November and December (UV index 2).

Average cloud cover in September
Fishtail, MT

Average cloud cover in September - Fishtail, MT
  • Average cloud cover in September: 18

The month with the most cloud cover is February (Cloud cover 38).
The months with the least cloud cover are July and August (Cloud cover 15).

Average visibility in September
Fishtail, MT

Average visibility in September - Fishtail, 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).

Fishtail, Montana, USA

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