September weather forecast
Alpine, TX

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The vast city of Alpine, Texas, with a view of the iconic Sul Ross State University in Brewster County
The vast city of Alpine, Texas, with a view of the iconic Sul Ross State University in Brewster County

Weather in September

September signals the starting of the fall season, showcasing the transformation from summer to cooler months. The month experiences a drop in temperatures and hours of daylight, indicating the approach of autumn. A noticeable surge in rainfall, reaching an annual high of 2.01" (51mm), brings along the typical fall weather. Meanwhile, the number of sunshine days decreases slightly from August. As this transition occurs, a mild drop in wind speed, down to 7.6mph (12.2km/h), adds to the peace of the month.

Temperature

With the commencement of September, Alpine records a moderate temperature decline, with the average high easing from August's tropical 88°F (31.1°C) to a warm 81.1°F (27.3°C). Alpine in September experiences a low-temperature average of 63.3°F (17.4°C).

Heat index

The heat index value for September is calculated to be 82.4°F (28°C). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.
When referencing the heat index, its values are suitable for shady environments and light breezes. Exposure to the sun directly might heighten the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is a single figure representing how weather conditions feel when combining temperature and humidity. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. Consider that direct sun exposure can intensify the felt heat, adding potentially 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values remain especially vital for babies and toddlers. Typically, young kids are at a higher risk than adults since they sweat less. Also, the larger skin surface in proportion to their small bodies and the heightened heat production due to their active nature adds to their vulnerability.

Humidity

September is the most humid month, with an average relative humidity of 56%.

Rainfall

The month with the most rainfall is September, when the rain falls for 14 days and typically aggregates up to 2.01" (51mm) of precipitation.

Snowfall

April through September are months without snowfall.

Daylight

In September, the average length of the day is 12h and 20min.
On the first day of September, sunrise is at 7:31 am and sunset at 8:16 pm. On the last day of the month, sunrise is at 7:47 am and sunset at 7:40 pm CDT.

Sunshine

The average sunshine in September in Alpine is 9.5h.

UV index

In Alpine, the average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV rays for the ordinary person.
Note: A daily high UV index of 6 in September leads to these guidelines:
Take precautions and utilize sun safety practices. Protection against skin and eye damage is required. Stay in the shade and limit sun exposure from 10 a.m. to 4 p.m., when UV radiation is most potent. Keep in mind that shade structures like parasols or canopies do not offer full protection. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses.
Updated: Jun 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

During September, Alpine experiences an average high-temperature of 81.1°F (27.3°C) and a low-temperature of 63.3°F (17.4°C). The average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines relative humidity and air temperature, in September is calculated to be 82.4°F (28°C).

What is the most humid month?

With an average relative humidity of 56%, September is the most humid month.

What is the average humidity in September?

The average relative humidity in September is 56%.

What is the rainiest month?

The month with the most rainfall is September, when the rain falls for 14 days and typically aggregates up to 2.01" (51mm) of precipitation.

How much does it rain in September?

In Alpine, in September, during 14 rainfall days, 2.01" (51mm) of precipitation is typically accumulated.

When it does not snow?

In Alpine, snow does not fall in April through September.

Does it snow in September?

In Alpine, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Alpine have in September?

In Alpine, Texas, the average day length in September is 12h and 20min.

When are sunrise and sunset in September?

On the first day of September, sunrise is at 7:31 am and sunset at 8:16 pm. On the last day of the month, sunrise is at 7:47 am and sunset at 7:40 pm CDT.

How many hours of sunshine does Alpine have in September?

The average sunshine duration in September is 9.5h.

What is the UV index intensity in September?

The average daily maximum UV index in September in Alpine, Texas, is 6. A UV Index value of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Alpine, TX

Average temperature in September - Alpine, TX
  • Average high temperature in September: 81.1°F

The warmest month (with the highest average high temperature) is June (90°F).
The month with the lowest average high temperature is January (56.8°F).

  • Average low temperature in September: 63.3°F

The months with the highest average low temperature are July and August (69.4°F).
The coldest month (with the lowest average low temperature) is January (37.4°F).

Average pressure in September
Alpine, TX

Average pressure in September - Alpine, TX
  • Average pressure in September: 29.94"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The months with the lowest atmospheric pressure are May and June (29.84"Hg).

Average wind speed in September
Alpine, TX

Average wind speed in September - Alpine, TX
  • Average wind speed in September: 7.6mph

The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is September (7.6mph).

Average humidity in September
Alpine, TX

Average humidity in September - Alpine, TX
  • Average humidity in September: 56%

The month with the highest relative humidity is September (56%).
The month with the lowest relative humidity is April (29%).

Average rainfall in September
Alpine, TX

Average rainfall in September - Alpine, TX
  • Average rainfall in September: 2.01"

The wettest month (with the highest rainfall) is September (2.01").
The driest month (with the least rainfall) is February (0.2").

Average rainfall days in September
Alpine, TX

Average rainfall days in September - Alpine, TX
  • Average rainfall days in September: 14 days

The month with the highest number of rainy days is July (15.1 days).
The month with the least rainy days is February (2.2 days).

Average snowfall in September
Alpine, TX

Average snowfall in September - Alpine, TX
  • Average snowfall in September: 0"

The month with the highest snowfall is January (0.67").
The months with the least snowfall are April, May, June, July, August and September (0").

Average snowfall days in September
Alpine, TX

Average snowfall days in September - Alpine, TX
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is December (1.6 days).
The months with the least snowfall days are April, May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Alpine, TX

Average daylight in September / Average sunshine in September - Alpine, TX
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 6min).
The month with the shortest days is December (Average daylight: 10h and 12min).

  • Average sunshine in September: 9h and 3min

The month with the most sunshine is June (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 7h and 42min).

Average sunshine days in September
Alpine, TX

Average sunshine days in September - Alpine, TX
  • Average sunshine days in September: 12.3 days

The month with the most sunshine days is January (26.8 days).
The month with the least sunshine days is July (11.7 days).

Average UV index in September
Alpine, TX

Average UV index in September - Alpine, TX
  • Average UV index in September: 6

The months with the highest UV index are May, June and July (UV index 7).
The months with the lowest UV index are January and December (UV index 3).

Average cloud cover in September
Alpine, TX

Average cloud cover in September - Alpine, TX
  • Average cloud cover in September: 22

The month with the most cloud cover is September (Cloud cover 22).
The month with the least cloud cover is June (Cloud cover 12).

Average visibility in September
Alpine, TX

Average visibility in September - Alpine, TX
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Alpine, Texas, USA

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