September Weather in Alpine, United States

Last updated: June 24, 2025

In September, the average temperature in Alpine, United States hovers around 11°C (53°F). Expect a minimum of -6°C (21°F) and a maximum of 29°C (85°F). During this month, precipitation amounts to 53 mm (2.1 in) over approximately 7 days, with an average humidity of 52%. Be prepared for fluctuating weather conditions!

September Temperature in Alpine

In September in Alpine, the average temperature is 11°C (53°F), with maximums reaching 29°C (85°F) and minimums dropping as low as -6°C (21°F). Whether you're looking to enjoy mild days or prepare for chilly evenings, this month's varied temperatures make it essential to pack accordingly for your travels.

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

The chart illustrates September temperature patterns in Alpine, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Alpine, September typically has an average temperature of 11°C (53°F), with highs reaching up to 29°C (85°F) and lows dropping to around -6°C (21°F).

Data source: Temperature data for Alpine generated using information from the Copernicus Climate Change Service.

September Precipitation in Alpine

In Alpine in September, the total precipitation amount is 53 mm (2.1 in) spread over a period of 7 days.

September Precipitation Trends in Alpine

The chart displays monthly precipitation patterns in Alpine, 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 Alpine, September typically receives around 53 mm (2.1 inches) of precipitation spread over approximately 7 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Alpine

In Alpine in September humidity is 52%. With an average temperature of 11°C (53°F), this humidity feels like a cool breeze that adds a refreshing touch to your travels, making it comfortable to explore outdoor attractions without feeling overheated.

September Average Humidity in Alpine

This chart illustrates the average monthly humidity levels in Alpine, 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 Alpine is approximately 52%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Alpine

In Alpine 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 Alpine.

Maximum UV Index Levels in Alpine for September

The chart shows the monthly maximum UV Index (UVI) for Alpine 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 Alpine typically reaches 9, which falls under the very high exposure category.

Data source: Alpine 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 Alpine Compares to Other Months

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

This table compares monthly weather conditions in Alpine, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-7°C (20°F)	87 mm (3.4 inches)	95%	moderate
February Weather	-6°C (21°F)	135 mm (5.3 inches)	95%	moderate
March Weather	-1°C (30°F)	70 mm (2.8 inches)	90%	very high
April Weather	1°C (34°F)	94 mm (3.7 inches)	81%	very high
May Weather	5°C (41°F)	63 mm (2.5 inches)	71%	extreme
June Weather	13°C (55°F)	53 mm (2.1 inches)	64%	extreme
July Weather	18°C (64°F)	20 mm (0.8 inches)	59%	extreme
August Weather	17°C (62°F)	27 mm (1.1 inches)	49%	extreme
September Weather	11°C (53°F)	53 mm (2.1 inches)	52%	very high
October Weather	3°C (37°F)	65 mm (2.6 inches)	69%	high
November Weather	-3°C (27°F)	87 mm (3.4 inches)	86%	moderate
December Weather	-7°C (20°F)	88 mm (3.5 inches)	91%	moderate