September weather forecast
Islitas, TX

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Weather in September

September, the first month of the autumn in Islitas, is still a tropical month, with temperature in the range of an average high of 92.5°F (33.6°C) and an average low of 76.1°F (24.5°C).

Temperature

The arrival of September is marked by a minor reduction in average high-temperature, sliding from a sweltering 100°F (37.8°C) in August to a hot 92.5°F (33.6°C). The nighttime temperature dips to a warm 76.1°F (24.5°C) on average during September.

Heat index

During September, the heat index is appraised at an extremely hot 105.8°F (41°C). Exercise heightened safety, heat cramps and heat exhaustion are probable. Persistent activity may provoke heatstroke.
For clarity, heat index numbers account for light winds and areas under shade. Heat index values may be hiked up by 15 Fahrenheit (8 Celsius) degrees under direct sunshine.
Note: The heat index, also known as 'apparent temperature' or 'real feel', is what the temperature feels like to the human body when the air temperature is combined with the relative humidity. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. In direct sunlight, the heat's impact can be heightened, potentially leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Youths are typically more endangered than adults since they usually sweat less. Their larger skin surface concerning their smaller bodies and higher heat production due to activity further adds to their vulnerability.
In the face of high temperatures, the human body's reflex is to perspire, leveraging sweat evaporation for cooling. During high air temperature and humidity (high heat index), the process of perspiration is hindered, intensifying the sensation of heat. As the body accumulates more heat than it can release, body temperature goes up, increasing the risk of heat-related health issues.

Humidity

In September, the average relative humidity is 60%.

Rainfall

September is the month with the most rainfall. Rain falls for 12.9 days and accumulates 2.17" (55mm) of precipitation.

Snowfall

March through November are months without snowfall.

Daylight

In Islitas, the average length of the day in September is 12h and 19min.
On the first day of the month, sunrise is at 7:17 am and sunset at 7:58 pm. On the last day of September, sunrise is at 7:31 am and sunset at 7:25 pm CDT.

Sunshine

In Islitas, Texas, the average sunshine in September is 8.6h.

UV index

The average daily maximum UV index in September is 7. A UV Index of 6 to 7 symbolizes a high health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: In September, a daily maximum UV index of 7 leads to the following instructions:
Dodge overexposure. Fair-skinned people can get singed in less than 20 minutes. Between 10 a.m. and 4 p.m., the Sun's UV radiation is at its peak. Limit your exposure to direct sunlight during these hours. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Updated: Jun 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is it in September?

An average high-temperature, in September, in Islitas, is 92.5°F (33.6°C) and the average low-temperature is 76.1°F (24.5°C). The average heat index (a.k.a. 'feels like', 'real feel'), which calculates the temperature value influenced by the moisture in the air, in September is appraised at 105.8°F (41°C).

What is the average humidity in September in Islitas?

The average relative humidity in September is 60%.

What is the rainiest month?

September is the month with the most rainfall. Rain falls for 12.9 days and accumulates 2.17" (55mm) of precipitation.

How many days does it rain in September?

In Islitas, during September, the rain falls for 12.9 days and regularly aggregates up to 2.17" (55mm) of precipitation.

When it does not snow?

In Islitas, snow does not fall in March through November.

How many hours of daylight does Islitas have in September?

The average day length in September is 12h and 19min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 7:17 am and sunset at 7:58 pm. On the last day of the month, in Islitas, sunrise is at 7:31 am and sunset at 7:25 pm CDT.

How long on average sun shines in September?

In September, the average sunshine duration is 8.6h.

How high is the UV index in September?

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

Average temperature in September
Islitas, TX

Average temperature in September - Islitas, TX
  • Average high temperature in September: 92.5°F

The warmest month (with the highest average high temperature) is August (100°F).
The month with the lowest average high temperature is January (66.9°F).

  • Average low temperature in September: 76.1°F

The month with the highest average low temperature is August (79.9°F).
The coldest month (with the lowest average low temperature) is January (50.2°F).

Average pressure in September
Islitas, TX

Average pressure in September - Islitas, TX
  • Average pressure in September: 29.92"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are May and June (29.86"Hg).

Average wind speed in September
Islitas, TX

Average wind speed in September - Islitas, TX
  • Average wind speed in September: 10mph

The windiest month (with the highest average wind speed) is July (13.5mph).
The calmest month (with the lowest average wind speed) is December (8.9mph).

Average humidity in September
Islitas, TX

Average humidity in September - Islitas, TX
  • Average humidity in September: 60%

The month with the highest relative humidity is December (62%).
The month with the lowest relative humidity is August (49%).

Average rainfall in September
Islitas, TX

Average rainfall in September - Islitas, TX
  • Average rainfall in September: 2.17"

The wettest month (with the highest rainfall) is September (2.17").
The driest month (with the least rainfall) is February (0.43").

Average rainfall days in September
Islitas, TX

Average rainfall days in September - Islitas, TX
  • Average rainfall days in September: 12.9 days

The month with the highest number of rainy days is September (12.9 days).
The month with the least rainy days is November (5.5 days).

Average snowfall days in September
Islitas, TX

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

The month with the highest number of snowfall days is January (0.2 days).
The months with the least snowfall days are March, April, May, June, July, August, September, October and November (0 days).

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

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

The month with the longest days is June (Average daylight: 13h and 54min).
The month with the shortest days is December (Average daylight: 10h and 24min).

  • Average sunshine in September: 8h and 4min

The month with the most sunshine is July (Average sunshine: 11h and 12min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).

Average sunshine days in September
Islitas, TX

Average sunshine days in September - Islitas, TX
  • Average sunshine days in September: 15.1 days

The month with the most sunshine days is January (23.3 days).
The month with the least sunshine days is September (15.1 days).

Average UV index in September
Islitas, TX

Average UV index in September - Islitas, TX
  • Average UV index in September: 7

The months with the highest UV index are July and August (UV index 8).
The months with the lowest UV index are January and December (UV index 4).

Average cloud cover in September
Islitas, TX

Average cloud cover in September - Islitas, TX
  • Average cloud cover in September: 30

The month with the most cloud cover is December (Cloud cover 36).
The month with the least cloud cover is August (Cloud cover 17).

Average visibility in September
Islitas, TX

Average visibility in September - Islitas, 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).

Islitas, Texas, USA

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