September weather forecast
Galveston, TX

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the colorful red night sky in the seaside city of Galveston in Texas
the colorful red night sky in the seaside city of Galveston in Texas

Weather in September

With the advent of September, Galveston starts bidding farewell to the summer and welcoming Fall. September sets the peak annual rainfall record with an average of 4.29". Despite this shift, the sea remains warm, and the breeze is consistent, providing solace from the remaining heat of summer days. As days become shorter, the decreasing temperature sees a reduction of outdoor and beach activities. The usual vibrant summer atmosphere gradually tapers off as the city starts transitioning towards cooler months.

Temperature

The unfolding of September in Galveston shows an average high-temperature of a warm 84.2°F, indicating a slight variance from August's 87.4°F. During September, the nighttime temperatures in Galveston, Texas, align closely with the daytime averages, measuring 78.4°F.

Heat index

The average heat index in September is computed to be a tropical 93.2°F. Ensure extra safety steps, heat exhaustion and heat cramps are likely. Long activity might lead to heatstroke.
In terms of the heat index, values are set with light wind and shade conditions in mind. Exposure to direct sunlight may make the heat index values climb by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', provides an understanding of perceived warmth by combining temperature and relative humidity. This effect is personal, influenced by the individual's physical activity and heat sensitivity, shaped by factors including wind, attire, and metabolic variations. By being directly under the sun, it's possible for the felt temperature to increase by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular importance for children. Kids generally face higher risks than adults as they sweat less. Along with their large skin surface compared to their small bodies and higher heat production due to their activities, their vulnerability is increased.

Humidity

In September, the average relative humidity is 75%.

Rainfall

September is the month with the most rainfall. Rain falls for 19.9 days and accumulates 4.29" of precipitation.

Snowfall

In Galveston, snow does not fall in March through December.

Ocean temperature

In Galveston, in September, the average water temperature is 83.8°F.
Note: Between the temperatures of 77°F and 84.2°F, water is considered very warm, providing pleasure in water activities without discomfort over lengthy periods.

Daylight

The average length of the day in September in Galveston, Texas, is 12h and 20min.
On the first day of September, sunrise is at 6:56 am and sunset at 7:41 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 7:06 pm CDT.

Sunshine

The average sunshine in September in Galveston is 8.9h.

UV index

May through September, with an average maximum UV index of 7, are months with the highest UV index in Galveston. A UV Index of 6 to 7 symbolizes a high health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum UV index, 7 during September, leads to the following recommendations:
Steer clear of overexposure. Fair-skinned individuals can be scorched in less than 20 minutes. From 10 a.m. to 4 p.m., when UV radiation is at its strongest, limit direct exposure to the Sun and note that shade structures may not provide full sun protection. To cut down UV radiation exposure by about half, sport a wide-brim hat. Attention! The reflection of both water and sand can increase the intensity of UV rays.
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FAQ

How hot is September in Galveston?

In Galveston, 84.2°F is the average high-temperature and 78.4°F is the average low-temperature during September. The average heat index (a.k.a. 'felt air temperature', 'feels like'), which combines air temperature and relative humidity, in September is computed to be 93.2°F.

What is the average humidity in September in Galveston?

The average relative humidity in September is 75%.

What is the wettest month in Galveston?

September is the month with the most rainfall in Galveston. Rain falls for 19.9 days and accumulates 4.29" of precipitation.

How much does it rain in Galveston in September?

In Galveston, in September, during 19.9 rainfall days, 4.29" of precipitation is typically accumulated.

When it does not snow in Galveston?

In Galveston, Texas, snow does not fall in March through December.

What is the ocean temperature in September in Galveston?

In September, the average ocean temperature in Galveston is 83.8°F. Water temperature between 77°F and 84.2°F is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

How many hours of daylight does Galveston have in September?

The average day length in September is 12h and 20min.

When is the sunrise / sunset in September in Galveston?

In September, on the first day of the month, sunrise is at 6:56 am and sunset at 7:41 pm. On the last day of the month, in Galveston, sunrise is at 7:11 am and sunset at 7:06 pm CDT.

How many hours of sunshine does Galveston have in September?

In Galveston, Texas, the average sunshine duration in September is 8.9h.

What is the month with the highest UV index in Galveston?

May through September, with an average maximum UV index of 7, are months with the highest UV index in Galveston.

What is the UV index intensity in September in Galveston?

In Galveston, the average daily maximum UV index in September is 7. A UV Index value of 6 to 7 symbolizes a high health risk from unsafe exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average snowfall days
Average sea temperature
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Galveston, TX

Average temperature in September - Galveston, TX
  • Average high temperature in September: 84.2°F

The warmest month (with the highest average high temperature) is August (87.4°F).
The month with the lowest average high temperature is January (59.7°F).

  • Average low temperature in September: 78.4°F

The month with the highest average low temperature is August (81.9°F).
The coldest month (with the lowest average low temperature) is January (51.6°F).

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Average pressure in September
Galveston, TX

Average pressure in September - Galveston, TX
  • Average pressure in September: 29.96"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

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Average wind speed in September
Galveston, TX

Average wind speed in September - Galveston, TX
  • Average wind speed in September: 9.6mph

The windiest month (with the highest average wind speed) is April (12.9mph).
The calmest month (with the lowest average wind speed) is August (9.4mph).

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Average humidity in September
Galveston, TX

Average humidity in September - Galveston, TX
  • Average humidity in September: 75%

The months with the highest relative humidity are February and March (81%).
The month with the lowest relative humidity is October (72%).

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Average rainfall in September
Galveston, TX

Average rainfall in September - Galveston, TX
  • Average rainfall in September: 4.29"

The wettest month (with the highest rainfall) is September (4.29").
The driest months (with the least rainfall) are February and March (0.75").

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Average rainfall days in September
Galveston, TX

Average rainfall days in September - Galveston, TX
  • Average rainfall days in September: 19.9 days

The month with the highest number of rainy days is September (19.9 days).
The month with the least rainy days is January (10.1 days).

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Average snowfall days in September
Galveston, TX

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

The month with the highest number of snowfall days is January (0.3 days).
The months with the least snowfall days are March, April, May, June, July, August, September, October, November and December (0 days).

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Average sea temperature in September
Galveston, TX

Average sea temperature in September - Galveston, TX
  • Average sea temperature in September: 83.8°F

The best month for swimming (with the highest average sea temperature) is August (87.2°F).
The coldest month (with the lowest average sea temperature) is January (56.5°F).

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

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

The month with the longest days is June (Average daylight: 14h and 0min).
The month with the shortest days is December (Average daylight: 10h and 18min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is August (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 4h and 54min).

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Average sunshine days in September
Galveston, TX

Average sunshine days in September - Galveston, TX
  • Average sunshine days in September: 8.5 days

The month with the most sunshine days is January (18.2 days).
The month with the least sunshine days is August (8.3 days).

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Average UV index in September
Galveston, TX

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

The months with the highest UV index are May, June, July, August and September (UV index 7).
The months with the lowest UV index are January and December (UV index 4).

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Average cloud cover in September
Galveston, TX

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

The month with the most cloud cover is February (Cloud cover 49).
The months with the least cloud cover are June, July, August and October (Cloud cover 26).

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Average visibility in September
Galveston, TX

Average visibility in September - Galveston, 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).

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Galveston, Texas, USA

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