September weather forecast
Alta, WY

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Weather in September

September, the first month of the autumn in Alta, is also an enjoyable month, with an average temperature varying between 64.9°F (18.3°C) and 40.1°F (4.5°C).

Temperature

The shift from August to September involves a decrease in the average high-temperature, dropping from a warm 74.1°F (23.4°C) to a refreshing 64.9°F (18.3°C). Despite drastic daily temperature oscillations, Alta cools down to an average low-temperature of 40.1°F (4.5°C) in September.

Humidity

In Alta, the average relative humidity in September is 54%.

Rainfall

In Alta, during September, the rain falls for 9.5 days and regularly aggregates up to 1.65" (42mm) of precipitation. In Alta, Wyoming, during the entire year, the rain falls for 96.6 days and collects up to 32.95" (837mm) of precipitation.

Snowfall

Months with snowfall are January through June, August through December. In September, it is snowing for 2.5 days. Throughout September, 4.49" (114mm) of snow is accumulated. Throughout the year, in Alta, there are 160.8 snowfall days, and 200.16" (5084mm) of snow is accumulated.

Daylight

In September, the average length of the day is 12h and 29min.
On the first day of September in Alta, sunrise is at 6:48 am and sunset at 7:59 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 7:06 pm MDT.

Sunshine

The average sunshine in September is 9.9h.

UV index

The average daily maximum UV index in September in Alta, Wyoming, is 3. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the average person.
Note: In September, a daily UV index of 3 turns into the following recommendations:
Take care. Persons with lighter skin might suffer burns in less than 30 minutes. Direct Sun exposure should be minimized especially during midday when radiation is most intense. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Consider carefully! The reflective quality of snow can almost double the intensity of the Sun's UV radiation.
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Frequently asked questions

What are the temperatures in Alta in September?

September temperatures in Alta vary between a high-temperature of 64.9°F (18.3°C) and a low-temperature of 40.1°F (4.5°C).

What is the average humidity in September in Alta?

In September, the average relative humidity is 54%.

How many days does it rain in September in Alta?

In Alta, Wyoming, during September, the rain falls for 9.5 days and regularly aggregates up to 1.65" (42mm) of precipitation.

How many days does it snow in September in Alta?

In Alta, in September, snow falls for 2.5 days, with typically accumulated 4.49" (114mm) of snow.

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

In Alta, the average day length in September is 12h and 29min.

When is the sunrise / sunset in September in Alta?

In September, on the first day of the month, sunrise is at 6:48 am and sunset at 7:59 pm. On the last day of the month, in Alta, Wyoming, sunrise is at 7:21 am and sunset at 7:06 pm MDT.

How many hours of sunshine does Alta have in September?

In September, the average sunshine duration in Alta, Wyoming, is 9.9h.

What is the UV index intensity in September in Alta?

In September, the average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a medium hazard to health from exposure to the Sun's UV radiation.
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
Alta, WY

Average temperature in September - Alta, WY
  • Average high temperature in September: 64.9°F

The warmest month (with the highest average high temperature) is July (75.4°F).
The month with the lowest average high temperature is December (23.2°F).

  • Average low temperature in September: 40.1°F

The month with the highest average low temperature is July (46.9°F).
The coldest month (with the lowest average low temperature) is December (7.7°F).

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Average pressure in September
Alta, WY

Average pressure in September - Alta, WY
  • Average pressure in September: 29.99"Hg

The month with the highest atmospheric pressure is January (30.27"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

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Average wind speed in September
Alta, WY

Average wind speed in September - Alta, WY
  • Average wind speed in September: 5.6mph

The windiest month (with the highest average wind speed) is June (6.2mph).
The calmest months (with the lowest average wind speed) are January and December (4.8mph).

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Average humidity in September
Alta, WY

Average humidity in September - Alta, WY
  • Average humidity in September: 54%

The month with the highest relative humidity is February (94%).
The month with the lowest relative humidity is August (47%).

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Average rainfall in September
Alta, WY

Average rainfall in September - Alta, WY
  • Average rainfall in September: 1.65"

The wettest month (with the highest rainfall) is February (4.13").
The driest month (with the least rainfall) is July (0.91").

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Average rainfall days in September
Alta, WY

Average rainfall days in September - Alta, WY
  • Average rainfall days in September: 9.5 days

The month with the highest number of rainy days is May (15.5 days).
The month with the least rainy days is January (3 days).

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Average snowfall in September
Alta, WY

Average snowfall in September - Alta, WY
  • Average snowfall in September: 4.49"

The month with the highest snowfall is February (34.33").
The month with the least snowfall is July (0").

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Average snowfall days in September
Alta, WY

Average snowfall days in September - Alta, WY
  • Average snowfall days in September: 2.5 days

The month with the highest number of snowfall days is March (23.6 days).
The month with the least snowfall days is July (0.1 days).

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Average daylight in September /
Average sunshine in September
Alta, WY

Average daylight in September / Average sunshine in September - Alta, WY
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).

  • Average sunshine in September: 9h and 5min

The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 3h and 18min).

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Average sunshine days in September
Alta, WY

Average sunshine days in September - Alta, WY
  • Average sunshine days in September: 16.7 days

The month with the most sunshine days is July (20.3 days).
The month with the least sunshine days is April (6.2 days).

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Average UV index in September
Alta, WY

Average UV index in September - Alta, WY
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, March, October, November and December (UV index 1).

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Average cloud cover in September
Alta, WY

Average cloud cover in September - Alta, WY
  • Average cloud cover in September: 20

The month with the most cloud cover is February (Cloud cover 73).
The month with the least cloud cover is August (Cloud cover 14).

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Average visibility in September
Alta, WY

Average visibility in September - Alta, WY
  • Average visibility in September: 6mi

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

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Alta, Wyoming, USA

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