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September Weather in Idaho City, United States

Last updated: June 24, 2025

In September, the average temperature in Idaho City, United States hovers around 14°C (58°F). However, temperatures can vary significantly, with a minimum of -2°C (28°F) and a maximum reaching 33°C (92°F). Visitors can expect about 31 mm (1.2 in) of precipitation spread over 4 days, while the average humidity sits at a comfortable 48%.

September Temperature in Idaho City

In September in Idaho City, the average temperature is 14°C (58°F). The maximum can reach 33°C (92°F), while the minimum can drop as low as -2°C (28°F). Be prepared for a wide range of temperatures during your travels in Idaho City this month.

September Weather in Idaho City: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Idaho City, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Idaho City, September typically has an average temperature of 14°C (58°F), with highs reaching up to 33°C (92°F) and lows dropping to around -2°C (28°F).
JanFebMarAprMayJunJulAugSepOctNovDec252635404959706858433325
Data source: Temperature data for Idaho City 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 Idaho City

In Idaho City in September, the total precipitation amount is 31 mm (1.2 in) over a span of 4 days.

September Precipitation Trends in Idaho City

The chart displays monthly precipitation patterns in Idaho City, 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 Idaho City, September typically receives around 31 mm (1.2 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec981269079684752131517785
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Idaho City

In Idaho City in September, humidity is 48%. With an average temperature of 14°C (58°F), this humidity feels like a refreshing embrace, making it comfortable for traveling as you can enjoy outdoor activities without feeling overly sticky or clammy.

September Average Humidity in Idaho City

This chart illustrates the average monthly humidity levels in Idaho City, 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 Idaho City is approximately 48%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%89%85%79%71%71%66%50%48%65%84%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Idaho City

In Idaho City in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Idaho City.

Maximum UV Index Levels in Idaho City for September

The chart shows the monthly maximum UV Index (UVI) for Idaho City 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 Idaho City typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3578111111109642
Data source: Idaho City 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 Idaho City Compares to Other Months

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

This table compares monthly weather conditions in Idaho City, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)98 mm (3.9 inches)88%moderate
February Weather-3°C (26°F)126 mm (5.0 inches)89%moderate
March Weather1°C (35°F)90 mm (3.6 inches)85%high
April Weather4°C (40°F)79 mm (3.1 inches)79%very high
May Weather9°C (49°F)68 mm (2.7 inches)71%extreme
June Weather15°C (60°F)47 mm (1.8 inches)71%extreme
July Weather21°C (70°F)5 mm (0.2 inches)66%extreme
August Weather20°C (68°F)20 mm (0.8 inches)50%very high
September Weather14°C (58°F)31 mm (1.2 inches)48%very high
October Weather6°C (43°F)51 mm (2.0 inches)65%high
November Weather1°C (33°F)77 mm (3.0 inches)84%moderate
December Weather-4°C (25°F)85 mm (3.4 inches)87%low

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