September weather forecast
Greybull, WY

Weather in September

September, the first month of the autumn in Greybull, is also an agreeable month, with an average temperature varying between 53.8°F (12.1°C) and 73.2°F (22.9°C).

Temperature

In September, the average high-temperature drops from a warm 82.6°F (28.1°C) in August to an agreeable 73.2°F (22.9°C). In Greybull, the average low-temperature is 53.8°F (12.1°C).

Humidity

In Greybull, the average relative humidity in September is 36%.

Rainfall

In Greybull, during September, the rain falls for 6.6 days and regularly aggregates up to 0.71" (18mm) of precipitation. Throughout the year, in Greybull, there are 103.2 rainfall days, and 5.71" (145mm) of precipitation is accumulated.

Snowfall

In Greybull, snow does not fall in June through September.

Daylight

The average length of the day in September in Greybull is 12h and 30min.
On the first day of September, sunrise is at 6:35 am and sunset at 7:49 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 6:55 pm MDT.

Sunshine

In September, the average sunshine in Greybull is 10.9h.

UV index

In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for ordinary individuals.
Note: In September, the average maximum UV index of 4 translate into the following recommendations:
Take precautions. Light skin individuals may get burned in less than 30 minutes. 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. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the average humidity in September in Greybull?

The average relative humidity in September is 36%.

How many days does it rain in September in Greybull?

In September, in Greybull, the rain falls for 6.6 days. Throughout September, 0.71" (18mm) of precipitation is accumulated.

When it does not snow in Greybull?

June through September are months without snowfall in Greybull.

Does it snow in Greybull in September?

In Greybull, Wyoming, in September, it doesn't snow. In October, it regularly snows.

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

In September, the average day length in Greybull, Wyoming, is 12h and 30min.

When is the sunrise / sunset in September in Greybull?

On the first day of September in Greybull, sunrise is at 6:35 am and sunset at 7:49 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 6:55 pm MDT.

How many hours of sunshine does Greybull have in September?

In Greybull, the average sunshine duration in September is 10.9h.

What is the UV index intensity in September in Greybull?

In September, the average daily maximum UV index in Greybull is 4. A UV Index reading of 3 to 5 represents a moderate vulnerability from unprotected exposure to UV radiation.

Average temperature in September
Greybull, WY

Average temperature in September - Greybull, WY
  • Average high temperature in September: 73.2°F

The warmest month (with the highest average high temperature) is July (85.1°F).
The month with the lowest average high temperature is December (28.8°F).

  • Average low temperature in September: 53.8°F

The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (13.8°F).

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Average pressure in September
Greybull, WY

Average pressure in September - Greybull, WY
  • Average pressure in September: 29.96"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

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Average wind speed in September
Greybull, WY

Average wind speed in September - Greybull, WY
  • Average wind speed in September: 6.6mph

The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest months (with the lowest average wind speed) are January and August (6mph).

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Average humidity in September
Greybull, WY

Average humidity in September - Greybull, WY
  • Average humidity in September: 36%

The month with the highest relative humidity is January (78%).
The months with the lowest relative humidity are July and August (33%).

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Average rainfall in September
Greybull, WY

Average rainfall in September - Greybull, WY
  • Average rainfall in September: 0.71"

The wettest month (with the highest rainfall) is May (0.87").
The driest month (with the least rainfall) is December (0.2").

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Average rainfall days in September
Greybull, WY

Average rainfall days in September - Greybull, WY
  • Average rainfall days in September: 6.6 days

The month with the highest number of rainy days is May (12.6 days).
The month with the least rainy days is December (6.5 days).

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Average snowfall in September
Greybull, WY

Average snowfall in September - Greybull, WY
  • Average snowfall in September: 0"

The month with the highest snowfall is February (2.52").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Greybull, WY

Average snowfall days in September - Greybull, WY
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is February (9.8 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
Greybull, WY

Average daylight in September / Average sunshine in September - Greybull, WY
  • Average daylight in September: 12h and 30min

The month with the longest days is June (Average daylight: 15h and 29min).
The month with the shortest days is December (Average daylight: 8h and 54min).

  • Average sunshine in September: 10.9h

The months with the most sunshine are June, July and August (Average sunshine: 11.9h).
The month with the least sunshine is January (Average sunshine: 6.7h).

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Average sunshine days in September
Greybull, WY

Average sunshine days in September - Greybull, WY
  • Average sunshine days in September: 18.5 days

The month with the most sunshine days is December (20.9 days).
The months with the least sunshine days are April and June (12.5 days).

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Average UV index in September
Greybull, WY

Average UV index in September - Greybull, WY
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

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Average cloud cover in September
Greybull, WY

Average cloud cover in September - Greybull, WY
  • Average cloud cover in September: 13

The month with the most cloud cover is February (Cloud cover 28).
The months with the least cloud cover are July and August (Cloud cover 12).

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Average visibility in September
Greybull, WY

Average visibility in September - Greybull, WY
  • 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).

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