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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 (66°F). However, be prepared for a range, as temperatures can dip to a chilly 2°C (35°F) and soar up to a sweltering 35°C (96°F). Rainfall totals around 111 mm (4.4 in) over 9 days, and humidity hovers at a high 79%, adding to the atmospheric feel of the region.

September Temperature in Wyoming

In September in Wyoming, the average temperature is 19°C (66°F). Maximums can reach 35°C (96°F), while minimums can drop as low as 2°C (35°F). Be prepared for a range of temperatures during your travels, so pack accordingly!

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 (66°F), with highs reaching up to 35°C (96°F) and lows dropping to around 2°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec262737465970757265533932
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 111 mm (4.4 in) over the course of 9 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 111 mm (4.4 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec6470679113811966741111306367
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 79%. With an average temperature of 19°C (66°F), this humidity feels like a warm embrace, making it feel much warmer than the actual temperature and creating a heavy, sticky atmosphere that can be a bit uncomfortable for traveling.

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 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%87%86%87%82%81%78%79%80%82%87%86%
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 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check 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 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24589101097532
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-3°C (26°F)64 mm (2.5 inches)87%low
February Weather-3°C (27°F)70 mm (2.7 inches)87%moderate
March Weather3°C (37°F)67 mm (2.6 inches)86%moderate
April Weather8°C (46°F)91 mm (3.6 inches)87%very high
May Weather15°C (60°F)138 mm (5.4 inches)82%very high
June Weather21°C (70°F)119 mm (4.7 inches)81%very high
July Weather24°C (75°F)65 mm (2.6 inches)78%very high
August Weather22°C (72°F)73 mm (2.9 inches)79%very high
September Weather19°C (66°F)111 mm (4.4 inches)79%high
October Weather12°C (53°F)130 mm (5.1 inches)82%moderate
November Weather4°C (39°F)63 mm (2.5 inches)87%moderate
December Weather0°C (32°F)67 mm (2.6 inches)86%low

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