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September Weather in Wyoming, United States

Last updated: June 24, 2025

In September, the average temperature in Wyoming, United States is a pleasant 19°C (67°F). Expect a range from a chilly 2°C (36°F) to a warm 33°C (92°F). During this month, you can anticipate around 127 mm (5.0 in) of precipitation spread over 10 days, contributing to an average humidity of 78%.

September Temperature in Wyoming

In September in Wyoming, the average temperature is 19°C (67°F), with maximums reaching 33°C (92°F) and minimums dropping as low as 2°C (36°F). This range makes it a great time to visit for those who enjoy mild weather but should be prepared for both warm days and cooler nights.

September Weather in Wyoming: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Wyoming, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Wyoming, September typically has an average temperature of 19°C (67°F), with highs reaching up to 33°C (92°F) and lows dropping to around 2°C (36°F).
JanFebMarAprMayJunJulAugSepOctNovDec212338486172757267533730
Data source: Temperature data for Wyoming generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Wyoming

In Wyoming in September, the precipitation amount is 127 mm (5.0 in), spread over a period of 10 days.

September Precipitation Trends in Wyoming

The chart displays monthly precipitation patterns in Wyoming, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Wyoming, September typically receives around 127 mm (5.0 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec4959738814011878911281244946
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Wyoming

In Wyoming in September humidity is 78%. With an average temperature of 19°C (67°F), this humidity feels like a warm, heavy blanket enveloping you, making traveling feel both sticky and sluggish as you navigate through the day.

September Average Humidity in Wyoming

This chart illustrates the average monthly humidity levels in Wyoming, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Wyoming is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec81%81%81%82%78%81%79%77%78%79%87%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Wyoming

In Wyoming in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Wyoming.

Maximum UV Index Levels in Wyoming for September

The chart shows the monthly maximum UV Index (UVI) for Wyoming in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Wyoming typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35689111098643
Data source: Wyoming September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How September Weather in Wyoming Compares to Other Months

Weather in Wyoming varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Wyoming, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Wyoming, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (22°F)49 mm (1.9 inches)81%moderate
February Weather-5°C (24°F)59 mm (2.3 inches)81%moderate
March Weather3°C (38°F)73 mm (2.9 inches)81%high
April Weather9°C (48°F)88 mm (3.5 inches)82%very high
May Weather16°C (62°F)140 mm (5.5 inches)78%very high
June Weather22°C (73°F)118 mm (4.6 inches)81%extreme
July Weather24°C (76°F)78 mm (3.1 inches)79%very high
August Weather22°C (72°F)91 mm (3.6 inches)77%very high
September Weather19°C (67°F)127 mm (5.0 inches)78%very high
October Weather11°C (53°F)124 mm (4.9 inches)78%high
November Weather3°C (38°F)49 mm (1.9 inches)87%moderate
December Weather-1°C (31°F)46 mm (1.8 inches)84%moderate

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