September Weather in Alpine, United States

Last updated: June 24, 2025

In September, the average temperature in Alpine, United States is a pleasant 23°C (73°F). However, be prepared for a range of temperatures: it can dip as low as 10°C (51°F) and soar up to 42°C (109°F). Expect minimal precipitation, averaging just 5 mm (0.2 in) over 1 day, and enjoy a comfortable average humidity of 52%.

September Temperature in Alpine

In September in Alpine, the average temperature is 23°C (73°F). The maximum can reach 42°C (109°F), while the minimum can dip as low as 10°C (51°F). Be sure to pack accordingly for both warm days and cooler evenings while exploring this destination.

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 23°C (73°F), with highs reaching up to 42°C (109°F) and lows dropping to around 10°C (51°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 precipitation amount is 5 mm (0.2 in) over a duration of 1 day.

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 5 mm (0.2 inches) of precipitation spread over approximately 1 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 23°C (73°F), this humidity feels like a comfortable embrace, making it pleasant for traveling as you can enjoy outdoor activities without feeling overheated or sticky.

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 reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, 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 11, which falls under the extreme 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	12°C (54°F)	70 mm (2.7 inches)	72%	moderate
February Weather	12°C (53°F)	86 mm (3.4 inches)	77%	high
March Weather	12°C (55°F)	71 mm (2.8 inches)	67%	very high
April Weather	15°C (60°F)	28 mm (1.1 inches)	56%	very high
May Weather	17°C (62°F)	27 mm (1.1 inches)	46%	extreme
June Weather	20°C (69°F)	2 mm (0.1 inches)	48%	extreme
July Weather	24°C (75°F)	7 mm (0.3 inches)	46%	extreme
August Weather	24°C (76°F)	4 mm (0.2 inches)	42%	extreme
September Weather	23°C (73°F)	5 mm (0.2 inches)	52%	extreme
October Weather	19°C (67°F)	15 mm (0.6 inches)	58%	very high
November Weather	16°C (61°F)	36 mm (1.4 inches)	66%	moderate
December Weather	12°C (54°F)	68 mm (2.7 inches)	74%	moderate