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September Weather in Caspar, United States

Last updated: June 24, 2025

In September, the average temperature in Caspar, United States is a pleasant 18°C (64°F). However, be prepared for temperature fluctuations, as it can dip as low as 8°C (47°F) or soar to a sweltering 36°C (96°F). During this month, expect 6 mm (0.2 in) of precipitation over approximately 1 day, accompanied by an average humidity of 68%.

September Temperature in Caspar

In September in Caspar, the average temperature is 18°C (64°F). Maximums can reach 36°C (96°F) and minimums can drop as low as 8°C (47°F). Be prepared for a wide range of temperatures when traveling, and pack accordingly!

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

The chart illustrates September temperature patterns in Caspar, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Caspar, September typically has an average temperature of 18°C (64°F), with highs reaching up to 36°C (96°F) and lows dropping to around 8°C (47°F).
JanFebMarAprMayJunJulAugSepOctNovDec505051545661636464595350
Data source: Temperature data for Caspar 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 Caspar

In Caspar in September, the precipitation amount is 6 mm (0.2 in) over the course of 1 day.

September Precipitation Trends in Caspar

The chart displays monthly precipitation patterns in Caspar, 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 Caspar, September typically receives around 6 mm (0.2 inches) of precipitation spread over approximately 1 days.
JanFebMarAprMayJunJulAugSepOctNovDec14813710860432216437297
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Caspar

In Caspar in September, humidity is 68%. With an average temperature of 18°C (64°F), this humidity feels like a warm embrace, making for a slightly muggy experience that can leave you feeling sticky as you explore, so it’s best to stay hydrated and take frequent breaks in the shade.

September Average Humidity in Caspar

This chart illustrates the average monthly humidity levels in Caspar, 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 Caspar is approximately 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%83%80%80%76%70%66%68%72%84%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Caspar

In Caspar 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 Caspar.

Maximum UV Index Levels in Caspar for September

The chart shows the monthly maximum UV Index (UVI) for Caspar 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 Caspar typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3578111111108643
Data source: Caspar 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 Caspar Compares to Other Months

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

This table compares monthly weather conditions in Caspar, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather10°C (50°F)147 mm (5.8 inches)86%moderate
February Weather10°C (50°F)137 mm (5.4 inches)84%moderate
March Weather10°C (51°F)108 mm (4.2 inches)83%high
April Weather12°C (54°F)60 mm (2.4 inches)80%very high
May Weather14°C (57°F)43 mm (1.7 inches)80%extreme
June Weather16°C (62°F)2 mm (0.1 inches)76%extreme
July Weather17°C (63°F)2 mm (0.1 inches)70%extreme
August Weather18°C (64°F)1 mm (0.0 inches)66%very high
September Weather18°C (64°F)6 mm (0.2 inches)68%very high
October Weather15°C (60°F)43 mm (1.7 inches)72%high
November Weather12°C (53°F)72 mm (2.8 inches)84%moderate
December Weather10°C (50°F)97 mm (3.8 inches)84%moderate

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