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September Weather in Polson, United States

Last updated: June 24, 2025

In Polson, United States, the average temperature in September is a pleasant 14°C (58°F). It can swing from a chilly -1°C (31°F) at its lowest to a warm 33°C (91°F) at its peak. Rainfall is relatively moderate, with 39 mm (1.5 in) spread over 8 days. You can expect an average humidity of 67%, making for a refreshing, balanced climate.

September Temperature in Polson

In September in Polson, the average temperature is 14°C (58°F), with maximums reaching 33°C (91°F) and minimums dropping to as low as -1°C (31°F). This varied climate makes Polson a destination where travelers should pack for both warm days and cool nights.

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

The chart illustrates September temperature patterns in Polson, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Polson, September typically has an average temperature of 14°C (58°F), with highs reaching up to 33°C (91°F) and lows dropping to around -1°C (31°F).
JanFebMarAprMayJunJulAugSepOctNovDec262334415260696858433529
Data source: Temperature data for Polson 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 Polson

In Polson in September, the precipitation amount is 39 mm (1.5 in) over the course of 8 days.

September Precipitation Trends in Polson

The chart displays monthly precipitation patterns in Polson, 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 Polson, September typically receives around 39 mm (1.5 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec518953787159162439717471
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Polson

In Polson in September, humidity is 67%. With an average temperature of 14°C (58°F), this humidity feels like a damp blanket enveloping you, making travel a bit uncomfortable as you navigate through the moist air.

September Average Humidity in Polson

This chart illustrates the average monthly humidity levels in Polson, 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 Polson is approximately 67%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec93%92%89%85%80%78%77%66%67%77%89%95%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Polson

In Polson 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 Polson.

Maximum UV Index Levels in Polson for September

The chart shows the monthly maximum UV Index (UVI) for Polson 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 Polson typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2467991097532
Data source: Polson 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 Polson Compares to Other Months

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

This table compares monthly weather conditions in Polson, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (27°F)51 mm (2.0 inches)93%low
February Weather-5°C (23°F)89 mm (3.5 inches)92%moderate
March Weather1°C (34°F)53 mm (2.1 inches)89%high
April Weather5°C (41°F)78 mm (3.1 inches)85%high
May Weather11°C (52°F)71 mm (2.8 inches)80%very high
June Weather16°C (60°F)59 mm (2.3 inches)78%very high
July Weather21°C (69°F)16 mm (0.6 inches)77%very high
August Weather20°C (68°F)24 mm (0.9 inches)66%very high
September Weather14°C (58°F)39 mm (1.5 inches)67%high
October Weather6°C (44°F)71 mm (2.8 inches)77%moderate
November Weather2°C (35°F)74 mm (2.9 inches)89%moderate
December Weather-1°C (30°F)71 mm (2.8 inches)95%low

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