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September Weather in Trail, United States

Last updated: June 24, 2025

In Trail, United States, the average temperature in September hovers around 16°C (61°F). Visitors can expect a range from a chilly 1°C (34°F) to a sweltering 36°C (98°F). During this month, the area experiences an average rainfall of 54 mm (2.1 in) spread over 6 days, contributing to an average humidity of 66%. Be prepared for a mix of weather as you explore!

September Temperature in Trail

In September in Trail, the average temperature is 16°C (61°F). Maximums can reach 36°C (98°F) and minimums can be as low as 1°C (34°F). Travelers should be prepared for a wide range of temperatures, making it essential to pack both light clothing for the heat and warmer layers for the cooler evenings.

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

The chart illustrates September temperature patterns in Trail, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Trail, September typically has an average temperature of 16°C (61°F), with highs reaching up to 36°C (98°F) and lows dropping to around 1°C (34°F).
JanFebMarAprMayJunJulAugSepOctNovDec373741475462696961504236
Data source: Temperature data for Trail 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 Trail

In Trail in September, the total precipitation amount is 54 mm (2.1 in) over the course of 6 days.

September Precipitation Trends in Trail

The chart displays monthly precipitation patterns in Trail, 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 Trail, September typically receives around 54 mm (2.1 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec1461701201115931175472117133
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Trail

In Trail in September humidity is 66%. With an average temperature of 16°C (61°F), this humidity feels like a heavy blanket enveloping you, making travel somewhat uncomfortable as the air grows sticky and tedious, slightly sapping your energy as you explore.

September Average Humidity in Trail

This chart illustrates the average monthly humidity levels in Trail, 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 Trail is approximately 66%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%85%86%83%83%83%78%67%66%77%87%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Trail

In Trail 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 Trail.

Maximum UV Index Levels in Trail for September

The chart shows the monthly maximum UV Index (UVI) for Trail 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 Trail typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3478111110108642
Data source: Trail 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 Trail Compares to Other Months

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

This table compares monthly weather conditions in Trail, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather3°C (37°F)145 mm (5.7 inches)84%moderate
February Weather3°C (37°F)170 mm (6.7 inches)85%moderate
March Weather5°C (41°F)119 mm (4.7 inches)86%high
April Weather8°C (47°F)111 mm (4.4 inches)83%very high
May Weather12°C (54°F)59 mm (2.3 inches)83%extreme
June Weather17°C (62°F)31 mm (1.2 inches)83%extreme
July Weather21°C (70°F)1 mm (0.0 inches)78%very high
August Weather20°C (69°F)7 mm (0.3 inches)67%very high
September Weather16°C (61°F)54 mm (2.1 inches)66%very high
October Weather10°C (50°F)72 mm (2.8 inches)77%high
November Weather5°C (42°F)117 mm (4.6 inches)87%moderate
December Weather2°C (36°F)133 mm (5.2 inches)87%low

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