September weather forecast
Joliet, MT

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Weather in September

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

Temperature

The start of September comes with a reduction in the average high-temperature, receding from a moderately hot 81.1°F (27.3°C) in August to a pleasant 72°F (22.2°C). Joliet anticipates a considerable daily temperature fluctuation in September, with low temperatures averaging a fresh 50.2°F (10.1°C).

Humidity

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

Rainfall

In Joliet, in September, during 6.9 rainfall days, 0.79" (20mm) of precipitation is typically accumulated. Throughout the year, there are 108.1 rainfall days, and 12.83" (326mm) of precipitation is accumulated.

Snowfall

January through June, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.8 snowfall days, it receives 0.67" (17mm) of snow. In Joliet, during the entire year, snow falls for 61.5 days and aggregates up to 41.77" (1061mm) of snow.

Daylight

In September, the average length of the day is 12h and 31min.
On the first day of the month, sunrise is at 6:38 am and sunset at 7:52 pm. On the last day of September, sunrise is at 7:13 am and sunset at 6:57 pm MDT.

Sunshine

The average sunshine in September is 10.6h.

UV index

The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the average person.
Note: In September, the maximum UV index of 4 translates into these guidelines:
Undertake protective steps - Recommendations to avoid sunburn are issued. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Be on the lookout! Nearly twofold UV radiation from the Sun can be reflected by snow.
Updated: Aug 28, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Joliet in September?

The average high-temperature, in September, in Joliet, is 72°F (22.2°C), while the average low-temperature is 50.2°F (10.1°C). The average heat index (a.k.a. 'real feel', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, in August is estimated at 80.6°F (27°C).

What is the average humidity in September?

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

How much does it rain in September?

In Joliet, in September, it is raining for 6.9 days, with typically 0.79" (20mm) of accumulated precipitation.

When does it start snowing?

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

How many hours of daylight does Joliet have in September?

The average day length in September in Joliet is 12h and 31min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:38 am and sunset at 7:52 pm. On the last day of the month, in Joliet, Montana, sunrise is at 7:13 am and sunset at 6:57 pm MDT.

How many hours of sunshine does Joliet have in September?

The average sunshine duration in September in Joliet is 10.6h.

What is the UV index reading in September in Joliet?

The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate health threat 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
Joliet, MT

Average temperature in September - Joliet, 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
Joliet, MT

Average pressure in September - Joliet, 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
Joliet, MT

Average wind speed in September - Joliet, 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
Joliet, MT

Average humidity in September - Joliet, 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
Joliet, MT

Average rainfall in September - Joliet, 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
Joliet, MT

Average rainfall days in September - Joliet, 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
Joliet, MT

Average snowfall in September - Joliet, 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
Joliet, MT

Average snowfall days in September - Joliet, 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
Joliet, MT

Average daylight in September / Average sunshine in September - Joliet, 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
Joliet, MT

Average sunshine days in September - Joliet, 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
Joliet, MT

Average UV index in September - Joliet, 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
Joliet, MT

Average cloud cover in September - Joliet, 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
Joliet, MT

Average visibility in September - Joliet, 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).

Joliet, Montana, USA

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