nomadseason

September Weather in Alta Sierra, United States

Last updated: June 24, 2025

In September, the average temperature in Alta Sierra, United States hovers around 20°C (68°F). Expect a wide range of temperatures, with minimums dipping to 1°C (35°F) and maximums peaking at 35°C (95°F). It's a relatively dry month, with total precipitation reaching only 5 mm (0.2 in) over the course of just one day. The average humidity is at a comfortable 48%, making for pleasant weather overall.

September Temperature in Alta Sierra

In September in Alta Sierra, the average temperature is 20°C (68°F). Maximums can reach 35°C (95°F), while minimums can be as low as 1°C (35°F). Be prepared for a wide range of temperatures when traveling during this time.

September Weather in Alta Sierra: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Alta Sierra, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Alta Sierra, September typically has an average temperature of 20°C (68°F), with highs reaching up to 35°C (95°F) and lows dropping to around 1°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec393943515768757468574839
Data source: Temperature data for Alta Sierra generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Alta Sierra

In Alta Sierra in September, the precipitation amount is 5 mm (0.2 in) over a duration of 1 day.

September Precipitation Trends in Alta Sierra

The chart displays monthly precipitation patterns in Alta Sierra, 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 Alta Sierra, September typically receives around 5 mm (0.2 inches) of precipitation spread over approximately 1 days.
JanFebMarAprMayJunJulAugSepOctNovDec102848941325535113470
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Alta Sierra

In Alta Sierra in September humidity is 48%. With an average temperature of 20°C (68°F), this humidity feels like a pleasant and refreshing environment for traveling, creating an ideal atmosphere for exploring and enjoying outdoor activities.

September Average Humidity in Alta Sierra

This chart illustrates the average monthly humidity levels in Alta Sierra, 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 Alta Sierra is approximately 48%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec78%82%76%68%58%52%46%39%48%59%72%76%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Alta Sierra

In Alta Sierra in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Alta Sierra.

Maximum UV Index Levels in Alta Sierra for September

The chart shows the monthly maximum UV Index (UVI) for Alta Sierra 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 Alta Sierra typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec469101112121110854
Data source: Alta Sierra 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 Alta Sierra Compares to Other Months

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

This table compares monthly weather conditions in Alta Sierra, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (39°F)102 mm (4.0 inches)78%moderate
February Weather4°C (40°F)84 mm (3.3 inches)82%high
March Weather6°C (43°F)89 mm (3.5 inches)75%very high
April Weather10°C (51°F)41 mm (1.6 inches)68%very high
May Weather14°C (57°F)32 mm (1.2 inches)57%extreme
June Weather20°C (69°F)5 mm (0.2 inches)52%extreme
July Weather24°C (76°F)5 mm (0.2 inches)46%extreme
August Weather23°C (74°F)3 mm (0.1 inches)39%extreme
September Weather20°C (68°F)5 mm (0.2 inches)48%very high
October Weather14°C (57°F)11 mm (0.4 inches)59%very high
November Weather9°C (48°F)34 mm (1.3 inches)72%moderate
December Weather4°C (40°F)70 mm (2.8 inches)76%moderate

Compare Alta Sierra's Climate with Cities Worldwide