Cheyenne
Wyoming, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Cheyenne, WY

A sunny day in the front of the State Capitol building in Cheyenne, Wyoming
A sunny day in the front of the State Capitol building in Cheyenne, Wyoming
September, the first month of the autumn, in Cheyenne, is also a moderately hot month, with average temperature varying between 73.8°F (23.2°C) and 52.3°F (11.3°C).

Temperature

In Cheyenne, the average high-temperature in September slightly decreases, from 81.1°F (27.3°C) in August, to a still moderately hot 73.8°F (23.2°C). The average low-temperature, is 52.3°F (11.3°C).

Humidity

In September, the average relative humidity is 44%.

Rainfall

In Cheyenne, in September, during 8.4 rainfall days, 0.87" (22mm) of precipitation is typically accumulated. In Cheyenne, during the entire year, the rain falls for 116 days and collects up to 14.57" (370mm) of precipitation.

Snowfall

June through September are months without snowfall in Cheyenne.

Daylight

In Cheyenne, the average length of the day in September is 12.4h.

Sunshine

The average sunshine in Cheyenne is 10.7h.

UV index

In Cheyenne, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unsafe exposure to the UV radiation for the ordinary person.
Note: The average daily UV index of 4 transform into the following instructions:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. 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. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.

What is the temperature in September in Cheyenne?

In September, in Cheyenne, the average high-temperature is 73.8°F (23.2°C), and the average low-temperature is 52.3°F (11.3°C).

What is the average humidity in September in Cheyenne?

The average relative humidity in September in Cheyenne is 44%.

How many days does it rain in September in Cheyenne?

In Cheyenne, in September, during 8.4 rainfall days, 0.87" (22mm) of precipitation is typically accumulated.

Does it snow in Cheyenne in September?

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

When it does not snow in Cheyenne?

In Cheyenne, Wyoming, snow does not fall in June through September.

How many hours of daylight does Cheyenne have in September?

The average length of the day in September in Cheyenne, Wyoming, is 12.4h.

How many hours of sunshine does Cheyenne have in September?

In September, the average sunshine is 10.7h.

What is the UV index intensity in September in Cheyenne?

The average daily maximum UV index in September in Cheyenne, Wyoming, is 4. A UV Index reading of 3 to 5 represents a medium hazard to health from unsafe exposure to the Sun's UV rays.
Average temperature in September - Cheyenne, WY
  • Average high temperature in September: 23.2°C

The warmest month (with the highest average high temperature) is July (28°C).
The month with the lowest average high temperature is December (1.5°C).

  • Average low temperature in September: 11.3°C

The month with the highest average low temperature is July (15.5°C).
The coldest month (with the lowest average low temperature) is December (-6.5°C).

Average humidity in September - Cheyenne, WY
  • Average humidity in September: 44%

The month with the highest relative humidity is February (64%).
The month with the lowest relative humidity is August (43%).

Average rainfall in September - Cheyenne, WY
  • Average rainfall in September: 22mm

The wettest month (with the highest rainfall) is May (75mm).
The driest month (with the lowest rainfall) is January (11mm).

Average rainfall days in September - Cheyenne, WY
  • Average rainfall days in September: 8.4 days

The month with the highest number of rainy days is May (17.5 days).
The month with the lowest number of rainy days is January (4.7 days).

Average snowfall in September - Cheyenne, WY
  • Average snowfall in September: 0mm

The month with the highest snowfall is March (154mm).
Months with the lowest snowfall are June, July, August and September (0mm).

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

The month with the highest number of snowfall days is February (11.3 days).
Months with the lowest number of snowfall days are June, July and August (0 days).

Average daylight in September / Average sunshine in September - Cheyenne, WY
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 15.1h).
The month with shortest days is December (Average daylight: 9.3h).

  • Average sunshine in September: 10.7h

Months with most sunshine are July and August (Average sunshine: 11.6h).
The month with least sunshine is February (Average sunshine: 6.5h).

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

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