September weather forecast and climate
Columbia Falls, MT

The first month of the autumn, September, is still a comfortable month in Columbia Falls, Montana, with average temperature varying between 65.5°F (18.6°C) and 39.2°F (4°C).

Temperature

In September, the average high-temperature drops, from a moderately hot 76.8°F (24.9°C) in August, to a comfortable 65.5°F (18.6°C). The average low-temperature, in Columbia Falls, Montana, is 39.2°F (4°C).

Humidity

The average relative humidity in September is 64%.

Rainfall

In Columbia Falls, it is raining for 8.5 days, with typically 0.71" (18mm) of accumulated precipitation. In Columbia Falls, during the entire year, the rain falls for 126.4 days and collects up to 11.22" (285mm) of precipitation.

Snowfall

January through May, September through December are months with snowfall in Columbia Falls. September is the first month it typically snows in Columbia Falls. Throughout September, in the average 0.3 snowfall days, it receives 0.04" (1mm) of snow. In Columbia Falls, during the entire year, snow falls for 97 days, and aggregates up to 33.86" (860mm) of snow.

Daylight

The average length of the day in September is 12.6h.

Sunshine

The average sunshine in September is 9.4h.

UV index

In September, the average daily maximum UV index in Columbia Falls, Montana, is 3. A UV Index reading of 3 to 5 represents a moderate health risk from the exposure to the Sun's UV radiation for the average person.
Note: The average daily UV index of 3 transform into the following instructions:
Take precautions - Protection against the skin and eye damage is obliged. 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. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.

What is the temperature in September in Columbia Falls?

In Columbia Falls, in September, the average high-temperature is 65.5°F (18.6°C), and the average low-temperature is 39.2°F (4°C).

What is the average humidity in September in Columbia Falls?

In September, the average relative humidity is 64%.

How much does it rain in Columbia Falls in September?

In Columbia Falls, Montana, in September, during 8.5 rainfall days, 0.71" (18mm) of precipitation is typically accumulated.

When does it start to snow in Columbia Falls?

September is the first month it typically snows. Throughout September, in the average 0.3 snowfall days, it receives 0.04" (1mm) of snow.

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

In September, the average length of the day in Columbia Falls is 12.6h.

How long on average sun shines in September in Columbia Falls?

The average sunshine in September in Columbia Falls is 9.4h.

What is the UV index intensity in September in Columbia Falls?

The average daily maximum UV index in September in Columbia Falls, Montana, is 3. A UV Index value of 3 to 5 symbolizes a medium health risk from unsafe exposure to the Sun's UV rays.
Average temperature in September - Columbia Falls, MT
  • Average high temperature in September: 18.6°C

The warmest month (with the highest average high temperature) is July (25.5°C).
The month with the lowest average high temperature is December (-3.5°C).

  • Average low temperature in September: 4°C

The month with the highest average low temperature is August (7.5°C).
The coldest month (with the lowest average low temperature) is February (-10.3°C).

Average pressure in September - Columbia Falls, MT
  • Average pressure in September: 1015mbar

The month with the highest atmospheric pressure is January (1021.4mbar).
The month with the lowest atmospheric pressure is June (1012.7mbar).

Average wind speed in September - Columbia Falls, MT
  • Average wind speed in September: 6.1km/h

The windiest month (with the highest average wind speed) is April (7.4km/h).
The calmest month (with the lowest average wind speed) is December (5.9km/h).

Average humidity in September - Columbia Falls, MT
  • Average humidity in September: 64%

The month with the highest relative humidity is January (93%).
The month with the lowest relative humidity is August (55%).

Average rainfall in September - Columbia Falls, MT
  • Average rainfall in September: 18mm

The wettest month (with the highest rainfall) is June (36mm).
The driest month (with the least rainfall) is August (11mm).

Average rainfall days in September - Columbia Falls, MT
  • Average rainfall days in September: 8.5 days

The month with the highest number of rainy days is April (15.8 days).
The month with the least rainy days is August (6.3 days).

Average snowfall in September - Columbia Falls, MT
  • Average snowfall in September: 1mm

The month with the highest snowfall is January (196mm).
Months with the least snowfall are June, July and August (0mm).

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

The month with the highest number of snowfall days is December (19.1 days).
Months with the least snowfall days are July and August (0 days).

Average daylight in September / Average sunshine in September - Columbia Falls, MT
  • Average daylight in September: 12.6h

The month with the longest days is June (Average daylight: 16h).
The month with the shortest days is December (Average daylight: 8.4h).

  • Average sunshine in September: 9.4h

The month with the most sunshine is July (Average sunshine: 11.9h).
The month with the least sunshine is January (Average sunshine: 3.5h).

Average sunshine days in September - Columbia Falls, MT
  • Average sunshine days in September: 19 days

The month with the most sunshine days is July (21.5 days).
The month with the least sunshine days is March (7.7 days).

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

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

Average cloud cover in September - Columbia Falls, MT
  • Average cloud cover in September: 24

The month with the most cloud cover is January (Cloud cover 65).
Months with the least cloud cover are July and August (Cloud cover 15).

Average visibility in September - Columbia Falls, MT
  • Average visibility in September: 9km

Months with the highest visibility are July and August (10km).
The month with the lowest visibility is January (5km).