September weather forecast
Afton, WY

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Weather in September

September witnesses a shift in narrative as Afton begins its transition from summer to fall. This month marks the first appearance of snow after the summer respite, albeit at a minimal 1.3" (33mm). The temperatures begin to fall as the daylight hours reduce, signaling the onset of autumn. The clear, star-studded skies of September nights and the gradual changes of fall colors during the day, make it a unique time to visit.

Temperature

Afton experiences a temperature shift at the start of September, with average high-temperatures adjusting from a warm 74.8°F (23.8°C) in August to a refreshing 65.7°F (18.7°C). In Afton, the September nights descend to a significantly cooler average of 39.7°F (4.3°C) compared to daytime highs.

Humidity

In Afton, the average relative humidity in September is 52%.

Rainfall

In September, the rain falls for 9.4 days. Throughout September, 1.3" (33mm) of precipitation is accumulated. In Afton, during the entire year, the rain falls for 109.5 days and collects up to 21.61" (549mm) of precipitation.

Snowfall

Months with snowfall are January through June, September through December. September is the first month it typically snows. Throughout September, in the average 1 snowfall days, it receives 1.3" (33mm) of snow. Throughout the year, there are 126.9 snowfall days, and 106.65" (2709mm) of snow is accumulated.

Daylight

The average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 6:49 am and sunset at 7:57 pm. On the last day of September, sunrise is at 7:20 am and sunset at 7:06 pm MDT.

Sunshine

In Afton, the average sunshine in September is 10.1h.

UV index

In September, the average daily maximum UV index in Afton is 3. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: In September, a regular UV index of 3 translates into these guidelines:
Ensure safety - Imperative it is to shield skin and eyes from damage. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
Updated: Aug 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September?

An average high-temperature, in September, in Afton, is 65.7°F (18.7°C) and the average low-temperature is 39.7°F (4.3°C).

What is the average humidity in September?

The average relative humidity in September is 52%.

How many days does it rain in September?

In Afton, during September, the rain falls for 9.4 days and regularly aggregates up to 1.3" (33mm) of precipitation.

When does it start to snow?

September is the first month it typically snows. Throughout September, in the average 1 snowfall days, it receives 1.3" (33mm) of snow.

What is the average length of the day in September?

In Afton, Wyoming, the average day length in September is 12h and 28min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:49 am and sunset at 7:57 pm. On the last day of the month, in Afton, sunrise is at 7:20 am and sunset at 7:06 pm MDT.

How many hours of sunshine does Afton have in September?

The average sunshine duration in September is 10.1h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 3. A UV Index estimate of 3 to 5 represents a medium health risk 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
Afton, WY

Average temperature in September - Afton, WY
  • Average high temperature in September: 65.7°F

The warmest month (with the highest average high temperature) is July (75.9°F).
The month with the lowest average high temperature is December (24.1°F).

  • Average low temperature in September: 39.7°F

The month with the highest average low temperature is July (45.7°F).
The coldest month (with the lowest average low temperature) is January (5.4°F).

Average pressure in September
Afton, WY

Average pressure in September - Afton, WY
  • Average pressure in September: 29.98"Hg

The month with the highest atmospheric pressure is January (30.29"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Afton, WY

Average wind speed in September - Afton, WY
  • Average wind speed in September: 5.2mph

The windiest month (with the highest average wind speed) is June (5.7mph).
The calmest months (with the lowest average wind speed) are January and December (4.2mph).

Average humidity in September
Afton, WY

Average humidity in September - Afton, WY
  • Average humidity in September: 52%

The month with the highest relative humidity is February (93%).
The month with the lowest relative humidity is August (45%).

Average rainfall in September
Afton, WY

Average rainfall in September - Afton, WY
  • Average rainfall in September: 1.3"

The wettest month (with the highest rainfall) is February (2.72").
The driest months (with the least rainfall) are July and August (0.63").

Average rainfall days in September
Afton, WY

Average rainfall days in September - Afton, WY
  • Average rainfall days in September: 9.4 days

The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is January (4.7 days).

Average snowfall in September
Afton, WY

Average snowfall in September - Afton, WY
  • Average snowfall in September: 1.3"

The month with the highest snowfall is February (19.96").
The months with the least snowfall are July and August (0").

Average snowfall days in September
Afton, WY

Average snowfall days in September - Afton, WY
  • Average snowfall days in September: 1 days

The month with the highest number of snowfall days is December (21.7 days).
The months with the least snowfall days are July and August (0 days).

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

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

The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in September: 10h and 1min

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 4h and 12min).

Average sunshine days in September
Afton, WY

Average sunshine days in September - Afton, WY
  • Average sunshine days in September: 17.5 days

The month with the most sunshine days is July (18.8 days).
The month with the least sunshine days is April (7 days).

Average UV index in September
Afton, WY

Average UV index in September - Afton, 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, November and December (UV index 1).

Average cloud cover in September
Afton, WY

Average cloud cover in September - Afton, WY
  • Average cloud cover in September: 16

The month with the most cloud cover is February (Cloud cover 63).
The months with the least cloud cover are July and August (Cloud cover 12).

Average visibility in September
Afton, WY

Average visibility in September - Afton, 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 and February (3mi).

Afton, Wyoming, USA

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