September weather forecast
Rim Rock Colony, MT

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Weather in September

The first month of the autumn, September, is also an enjoyable month in Rim Rock Colony, Montana, with temperature in the range of an average low of 48.4°F (9.1°C) and an average high of 67.6°F (19.8°C).

Temperature

As August transitions into September, Rim Rock Colony sees a drop in the average high-temperature, transitioning from a moderately hot 78.1°F (25.6°C) to an enjoyable 67.6°F (19.8°C). Throughout September, Rim Rock Colony experiences a low-temperature average of 48.4°F (9.1°C).

Humidity

The average relative humidity in September is 49%.

Rainfall

In Rim Rock Colony, in September, during 6.2 rainfall days, 0.71" (18mm) of precipitation is typically accumulated. Throughout the year, there are 70.4 rainfall days, and 8.46" (215mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.8 snowfall days, it receives 0.51" (13mm) of snow. Throughout the year, in Rim Rock Colony, there are 54.3 snowfall days, and 19.49" (495mm) of snow is accumulated.

Daylight

In Rim Rock Colony, the average length of the day in September is 12h and 34min.
On the first day of September, sunrise is at 6:46 am and sunset at 8:09 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 7:08 pm MDT.

Sunshine

In September, the average sunshine is 9.6h.

UV index

In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: The maximum UV index of 4 during September leads to these instructions:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Updated: Jul 19, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September?

The high-temperature, in September, in Rim Rock Colony, records 67.6°F (19.8°C), while the low-temperature is 48.4°F (9.1°C).

What is the average humidity in September?

The average relative humidity in September is 49%.

How many days does it rain in September?

In Rim Rock Colony, in September, during 6.2 rainfall days, 0.71" (18mm) of precipitation is typically accumulated.

When does it start snowing?

September is the first month it typically snows. Throughout September, in the average 0.8 snowfall days, it receives 0.51" (13mm) of snow.

What is the average length of the day in September?

In September, the average day length is 12h and 34min.

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:46 am and sunset at 8:09 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 7:08 pm MDT.

How many hours of sunshine does Rim Rock Colony have in September?

The average sunshine duration in September is 9.6h.

How high is the UV index in September in Rim Rock Colony?

In Rim Rock Colony, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health risk 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
Rim Rock Colony, MT

Average temperature in September - Rim Rock Colony, MT
  • Average high temperature in September: 67.6°F

The warmest month (with the highest average high temperature) is July (78.8°F).
The month with the lowest average high temperature is December (27.1°F).

  • Average low temperature in September: 48.4°F

The month with the highest average low temperature is August (55.2°F).
The coldest month (with the lowest average low temperature) is December (15.3°F).

Average pressure in September
Rim Rock Colony, MT

Average pressure in September - Rim Rock Colony, MT
  • Average pressure in September: 29.95"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

Average wind speed in September
Rim Rock Colony, MT

Average wind speed in September - Rim Rock Colony, MT
  • Average wind speed in September: 9.5mph

The windiest month (with the highest average wind speed) is January (11.8mph).
The calmest months (with the lowest average wind speed) are July and August (8.8mph).

Average humidity in September
Rim Rock Colony, MT

Average humidity in September - Rim Rock Colony, MT
  • Average humidity in September: 49%

The month with the highest relative humidity is January (79%).
The month with the lowest relative humidity is August (43%).

Average rainfall in September
Rim Rock Colony, MT

Average rainfall in September - Rim Rock Colony, MT
  • Average rainfall in September: 0.71"

The wettest month (with the highest rainfall) is June (1.77").
The driest month (with the least rainfall) is July (0.31").

Average rainfall days in September
Rim Rock Colony, MT

Average rainfall days in September - Rim Rock Colony, MT
  • Average rainfall days in September: 6.2 days

The month with the highest number of rainy days is May (10.4 days).
The month with the least rainy days is November (2.6 days).

Average snowfall in September
Rim Rock Colony, MT

Average snowfall in September - Rim Rock Colony, MT
  • Average snowfall in September: 0.51"

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

Average snowfall days in September
Rim Rock Colony, MT

Average snowfall days in September - Rim Rock Colony, MT
  • Average snowfall days in September: 0.8 days

The month with the highest number of snowfall days is December (10.2 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in September /
Average sunshine in September
Rim Rock Colony, MT

Average daylight in September / Average sunshine in September - Rim Rock Colony, MT
  • Average daylight in September: 12h and 4min

The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 18min).

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is July (Average sunshine: 12h and 0min).
The months with the least sunshine are January and December (Average sunshine: 5h and 36min).

Average sunshine days in September
Rim Rock Colony, MT

Average sunshine days in September - Rim Rock Colony, MT
  • Average sunshine days in September: 22.4 days

The month with the most sunshine days is July (23.5 days).
The month with the least sunshine days is April (17.4 days).

Average UV index in September
Rim Rock Colony, MT

Average UV index in September - Rim Rock Colony, 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
Rim Rock Colony, MT

Average cloud cover in September - Rim Rock Colony, MT
  • Average cloud cover in September: 23

The month with the most cloud cover is February (Cloud cover 43).
The month with the least cloud cover is July (Cloud cover 15).

Average visibility in September
Rim Rock Colony, MT

Average visibility in September - Rim Rock Colony, 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).

Rim Rock Colony, Montana, USA

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