September weather forecast
Thompson Falls, MT

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Weather in September

September in Thompson Falls signals the arrival of Autumn with noticeable subsiding high temperatures and an increase in rainfall. Thompson Falls celebrates the changing seasons, with the landscape gradually taking on best fall hues. The persistent sunshine from previous months starts to dwindle, in line with the slow, sure transit into Autumn. With the onset of cooler evenings, the town's residents start preparing for the impending cold season.

Temperature

With the beginning of September, the average high-temperature shows a decrease, transitioning from a warm 78.8°F (26°C) in August to a refreshing 67.3°F (19.6°C). Thompson Falls experiences a significant downturn from peak daytime temperatures throughout September, with the average low-temperature dipping to a wintry 39.7°F (4.3°C).

Humidity

In Thompson Falls, the average relative humidity in September is 63%.

Rainfall

In Thompson Falls, in September, it is raining for 7.8 days, with typically 0.59" (15mm) of accumulated precipitation. Throughout the year, in Thompson Falls, there are 152.1 rainfall days, and 22.09" (561mm) of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall in Thompson Falls. September is the first month it typically snows. Throughout September, in the average 0.3 snowfall days, it receives 0.31" (8mm) of snow. In Thompson Falls, Montana, during the entire year, snow falls for 90.2 days and aggregates up to 58.15" (1477mm) of snow.

Daylight

In September, the average length of the day is 12h and 33min.
On the first day of the month, sunrise is at 7:01 am and sunset at 8:21 pm. On the last day of September, sunrise is at 7:40 am and sunset at 7:21 pm MDT.

Sunshine

In Thompson Falls, the average sunshine in September is 9h.

UV index

In September, the average daily maximum UV index in Thompson Falls is 3. A UV Index of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for the average person.
Note: A maximum high daily UV index of 3 during September translates into the following directions:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.
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Frequently asked questions

What are September temperatures in Thompson Falls?

The high-temperature in Thompson Falls during September is 67.3°F (19.6°C) and the low-temperature is 39.7°F (4.3°C).

What is the average humidity in September in Thompson Falls?

In September, the average relative humidity in Thompson Falls is 63%.

How many days does it rain in September in Thompson Falls?

In Thompson Falls, during September, the rain falls for 7.8 days and regularly aggregates up to 0.59" (15mm) of precipitation.

When does it start to snow in Thompson Falls?

September is the first month it typically snows in Thompson Falls, Montana. Throughout September, in the average 0.3 snowfall days, it receives 0.31" (8mm) of snow.

How many hours of daylight does Thompson Falls have in September?

In Thompson Falls, Montana, the average day length in September is 12h and 33min.

What time are sunrise and sunset in September in Thompson Falls?

In September, on the first day of the month, sunrise is at 7:01 am and sunset at 8:21 pm. On the last day of the month, in Thompson Falls, sunrise is at 7:40 am and sunset at 7:21 pm MDT.

How many hours of sunshine does Thompson Falls have in September?

In September, the average sunshine duration in Thompson Falls is 9h.

How high is the UV index in September in Thompson Falls?

In Thompson Falls, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a moderate vulnerability from unsafe 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
Thompson Falls, MT

Average temperature in September - Thompson Falls, MT
  • Average high temperature in September: 67.3°F

The warmest months (with the highest average high temperature) are July and August (78.8°F).
The month with the lowest average high temperature is December (28.9°F).

  • Average low temperature in September: 39.7°F

The month with the highest average low temperature is August (45.7°F).
The coldest month (with the lowest average low temperature) is December (16.2°F).

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Average pressure in September
Thompson Falls, MT

Average pressure in September - Thompson Falls, MT
  • Average pressure in September: 29.98"Hg

The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

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Average wind speed in September
Thompson Falls, MT

Average wind speed in September - Thompson Falls, MT
  • Average wind speed in September: 4.2mph

The windiest month (with the highest average wind speed) is April (4.9mph).
The calmest month (with the lowest average wind speed) is December (4mph).

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Average humidity in September
Thompson Falls, MT

Average humidity in September - Thompson Falls, MT
  • Average humidity in September: 63%

The month with the highest relative humidity is January (93%).
The months with the lowest relative humidity are July and August (53%).

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Average rainfall in September
Thompson Falls, MT

Average rainfall in September - Thompson Falls, MT
  • Average rainfall in September: 0.59"

The wettest month (with the highest rainfall) is January (3.11").
The driest month (with the least rainfall) is August (0.39").

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Average rainfall days in September
Thompson Falls, MT

Average rainfall days in September - Thompson Falls, MT
  • Average rainfall days in September: 7.8 days

The month with the highest number of rainy days is March (19.9 days).
The month with the least rainy days is August (5.9 days).

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Average snowfall in September
Thompson Falls, MT

Average snowfall in September - Thompson Falls, MT
  • Average snowfall in September: 0.31"

The month with the highest snowfall is February (15.12").
The months with the least snowfall are June, July and August (0").

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Average snowfall days in September
Thompson Falls, MT

Average snowfall days in September - Thompson Falls, MT
  • Average snowfall days in September: 0.3 days

The month with the highest number of snowfall days is December (20.4 days).
The months with the least snowfall days are June, July and August (0 days).

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Average daylight in September /
Average sunshine in September
Thompson Falls, MT

Average daylight in September / Average sunshine in September - Thompson Falls, 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 0min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).

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Average sunshine days in September
Thompson Falls, MT

Average sunshine days in September - Thompson Falls, MT
  • Average sunshine days in September: 20.3 days

The months with the most sunshine days are July and August (23.3 days).
The month with the least sunshine days is March (5.8 days).

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Average UV index in September
Thompson Falls, MT

Average UV index in September - Thompson Falls, MT
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 1).

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Average cloud cover in September
Thompson Falls, MT

Average cloud cover in September - Thompson Falls, MT
  • Average cloud cover in September: 25

The month with the most cloud cover is February (Cloud cover 66).
The months with the least cloud cover are July and August (Cloud cover 15).

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Average visibility in September
Thompson Falls, MT

Average visibility in September - Thompson Falls, MT
  • Average visibility in September: 6mi

The months with the highest visibility are June, July, August and September (6mi).
The months with the lowest visibility are January, February and December (3mi).

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Thompson Falls, Montana, USA

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