September weather forecast
Harlingen, TX

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Weather in September

September, the first month of the autumn in Harlingen, is also a hot month, with an average temperature varying between 90.5°F (32.5°C) and 78.1°F (25.6°C).

Temperature

The average high-temperature for September is a tropical 90.5°F (32.5°C), closely aligning with the temperature of the preceding month. Throughout the nights in September, Harlingen experiences an average low-temperature of 78.1°F (25.6°C).

Heat index

The average heat index in September is estimated at a scorching 107.6°F (42°C). Exercise heightened safety, heat cramps and heat exhaustion are probable. Persistent activity may provoke heatstroke.
Be advised, the heat index considers values for conditions in shade and with a light breeze. 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 'felt air temperature', combines air temperature and relative humidity to represent a human perceived temperature equivalent. The individual's experience of temperature can be shaped by numerous aspects such as metabolic variations, physical exertion, and attire. It is noteworthy to mention that direct sunlight exposure can augment the felt temperature, leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Kids are generally in more danger than adults because they perspire less. Their large skin surface area compared to their small bodies and the excessive heat due to their actions raises their risk.
The innate cooling system of the human body revolves around perspiration, with the evaporation of sweat being central to this process. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. Rising body temperatures due to excess heat retention could signify impending heat disorders.

Humidity

In September, the average relative humidity is 69%.

Rainfall

In Harlingen, Texas, during September, the rain falls for 11.5 days and regularly aggregates up to 0.63" (16mm) of precipitation. In Harlingen, during the entire year, the rain falls for 79.8 days and collects up to 5.24" (133mm) of precipitation.

Snowfall

In Harlingen, snow does not fall in January, March through December.

Daylight

The average length of the day in September is 12h and 18min.
On the first day of September in Harlingen, sunrise is at 7:11 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 7:17 pm CDT.

Sunshine

In Harlingen, the average sunshine in September is 8.9h.

UV index

In September, the average daily maximum UV index is 7. A UV Index of 6 to 7 symbolizes a high health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: A maximum UV index of 7 in September translates into the following recommendations:
Employ safeguards and advocate sun safety protocols. Shielding against skin and eye damage is crucial. Try to minimize direct Sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Also note that objects like parasols or canopies might not provide complete sun protection. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Updated: Jul 21, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot does it get in September?

In Harlingen, 90.5°F (32.5°C) is the average high-temperature and 78.1°F (25.6°C) is the average low-temperature during September. In September, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which factors the actual air temperature with the relative humidity, is estimated at 107.6°F (42°C).

What is the average humidity in September?

In Harlingen, the average relative humidity in September is 69%.

How many days does it rain in September?

In Harlingen, during September, the rain falls for 11.5 days and regularly aggregates up to 0.63" (16mm) of precipitation.

When it does not snow?

January, March through December are months without snowfall.

What is the average length of the day in September in Harlingen?

In Harlingen, the average day length in September is 12h and 18min.

When are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 7:11 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 7:17 pm CDT.

How many hours of sunshine does Harlingen have in September?

In September, the average sunshine duration is 8.9h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 7. A UV Index value of 6 to 7 symbolizes a high health vulnerability 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
Harlingen, TX

Average temperature in September - Harlingen, TX
  • Average high temperature in September: 90.5°F

The warmest month (with the highest average high temperature) is August (95°F).
The month with the lowest average high temperature is January (68.7°F).

  • Average low temperature in September: 78.1°F

The month with the highest average low temperature is August (80.1°F).
The coldest month (with the lowest average low temperature) is January (55.4°F).

Average pressure in September
Harlingen, TX

Average pressure in September - Harlingen, TX
  • Average pressure in September: 29.91"Hg

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

Average wind speed in September
Harlingen, TX

Average wind speed in September - Harlingen, TX
  • Average wind speed in September: 8.9mph

The windiest months (with the highest average wind speed) are March and April (12.1mph).
The calmest month (with the lowest average wind speed) is September (8.9mph).

Average humidity in September
Harlingen, TX

Average humidity in September - Harlingen, TX
  • Average humidity in September: 69%

The month with the highest relative humidity is May (73%).
The month with the lowest relative humidity is August (65%).

Average rainfall in September
Harlingen, TX

Average rainfall in September - Harlingen, TX
  • Average rainfall in September: 0.63"

The wettest month (with the highest rainfall) is July (0.87").
The driest month (with the least rainfall) is February (0.16").

Average rainfall days in September
Harlingen, TX

Average rainfall days in September - Harlingen, TX
  • Average rainfall days in September: 11.5 days

The month with the highest number of rainy days is September (11.5 days).
The month with the least rainy days is February (4.7 days).

Average snowfall days in September
Harlingen, TX

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

The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).

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

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

The month with the longest days is June (Average daylight: 13h and 48min).
The month with the shortest days is December (Average daylight: 10h and 30min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is July (Average sunshine: 11h and 24min).
The month with the least sunshine is December (Average sunshine: 5h and 6min).

Average sunshine days in September
Harlingen, TX

Average sunshine days in September - Harlingen, TX
  • Average sunshine days in September: 15.6 days

The month with the most sunshine days is March (23.3 days).
The month with the least sunshine days is September (15.6 days).

Average UV index in September
Harlingen, TX

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

The month with the highest UV index is July (UV index 8).
The month with the lowest UV index is December (UV index 4).

Average cloud cover in September
Harlingen, TX

Average cloud cover in September - Harlingen, TX
  • Average cloud cover in September: 29

The month with the most cloud cover is December (Cloud cover 45).
The month with the least cloud cover is August (Cloud cover 18).

Average visibility in September
Harlingen, TX

Average visibility in September - Harlingen, 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).

Harlingen, Texas, USA

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