September weather forecast
Nassau Bay, TX

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Weather in September

September, the first month of the autumn in Nassau Bay, is still a hot month, with an average temperature fluctuating between 86.2°F (30.1°C) and 75.7°F (24.3°C).

Temperature

The arrival of September denotes a barely perceptible change in the average high-temperatures to a still hot 86.2°F (30.1°C) from August's 90.5°F (32.5°C). September nights are marked by an average low-temperature of 75.7°F (24.3°C).

Heat index

In September, the average heat index is calculated to be a very hot 98.6°F (37°C). Undertake extra safety actions, heat cramps and heat exhaustion are expected. Heatstroke may result from lengthy activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. The heat index can potentially augment by 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'real feel' or 'feels like', arises from combining readings of air temperature and relative moisture content. The influence of weather is personal, differing among individuals based on variations in body mass, stature, and the degree of physical exertion. When exposed to direct sunlight, it's possible for the heat index to increase by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Children often overlook the necessity for resting and fluid replenishment. Thirst is a late sign of dehydration - thus, it is critical to stay hydrated, especially during extended periods of physical activities.
Evaporating sweat, an outcome of perspiration, is key in assisting the human body to moderate its temperature. In high relative humidity, the body's ability to evaporate heat is diminished, resulting in a heightened feeling of warmth. When the body's heat gain surpasses its removal capacity, body temperature starts to climb, leading to potential heat-related ailments.

Humidity

In Nassau Bay, the average relative humidity in September is 75%.

Rainfall

September is the month with the most rainfall. Rain falls for 15.9 days and accumulates 1.5" (38mm) of precipitation.

Snowfall

January, September and December are months with snowfall. The months with the most snowfall days are January, September and December, with an average of 0.1 snowfall days.

Daylight

The average length of the day in September is 12h and 20min.
On the first day of September, sunrise is at 6:58 am and sunset at 7:42 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 7:06 pm CDT.

Sunshine

In Nassau Bay, the average sunshine in September is 8.6h.

UV index

The average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high health risk from exposure to the Sun's UV radiation for the average person.
Note: The UV index of 6 during September leads to these advisories:
Avert overexposure. Light-skinned people might experience burning in less than 20 minutes. Remember that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. Make an effort to avoid direct sun exposure during these hours. During bright days, sunglasses that offer UVA and UVB defense are recommended. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.
Updated: Jun 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is it in September?

In September, in Nassau Bay, the average high-temperature is 86.2°F (30.1°C), and the average low-temperature is 75.7°F (24.3°C). In September, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, is calculated to be 98.6°F (37°C).

What is the average humidity in September in Nassau Bay?

The average relative humidity in September is 75%.

What is the rainiest month?

The month with the most rainfall in Nassau Bay is September, when the rain falls for 15.9 days and typically aggregates up to 1.5" (38mm) of precipitation.

How much does it rain in September?

In Nassau Bay, in September, during 15.9 rainfall days, 1.5" (38mm) of precipitation is typically accumulated.

When does it snow the most?

The months with the most snowfall days are January, September and December, with an average of 0.1 snowfall days.

When does it start snowing?

September is the first month it typically snows. Throughout September, there are 0.1 snowfall days.

What is the average length of the day in September?

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

When are sunrise and sunset in September?

On the first day of September, sunrise is at 6:58 am and sunset at 7:42 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 7:06 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 in Nassau Bay?

In Nassau Bay, the average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health risk from exposure to Sun's UV rays.
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
Nassau Bay, TX

Average temperature in September - Nassau Bay, TX
  • Average high temperature in September: 86.2°F

The warmest month (with the highest average high temperature) is August (90.5°F).
The month with the lowest average high temperature is January (60.4°F).

  • Average low temperature in September: 75.7°F

The month with the highest average low temperature is August (79.7°F).
The coldest month (with the lowest average low temperature) is January (48.6°F).

Average pressure in September
Nassau Bay, TX

Average pressure in September - Nassau Bay, 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).

Average wind speed in September
Nassau Bay, TX

Average wind speed in September - Nassau Bay, TX
  • Average wind speed in September: 7.7mph

The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is August (7.6mph).

Average humidity in September
Nassau Bay, TX

Average humidity in September - Nassau Bay, TX
  • Average humidity in September: 75%

The month with the highest relative humidity is February (80%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
Nassau Bay, TX

Average rainfall in September - Nassau Bay, TX
  • Average rainfall in September: 1.5"

The wettest month (with the highest rainfall) is September (1.5").
The driest months (with the least rainfall) are February and March (0.31").

Average rainfall days in September
Nassau Bay, TX

Average rainfall days in September - Nassau Bay, TX
  • Average rainfall days in September: 15.9 days

The month with the highest number of rainy days is September (15.9 days).
The month with the least rainy days is February (6.3 days).

Average snowfall days in September
Nassau Bay, TX

Average snowfall days in September - Nassau Bay, TX
  • Average snowfall days in September: 0.1 days

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

Average daylight in September /
Average sunshine in September
Nassau Bay, TX

Average daylight in September / Average sunshine in September - Nassau Bay, 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 4min

The months with the most sunshine are July and August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 42min).

Average sunshine days in September
Nassau Bay, TX

Average sunshine days in September - Nassau Bay, TX
  • Average sunshine days in September: 10.3 days

The month with the most sunshine days is January (21.9 days).
The month with the least sunshine days is September (10.3 days).

Average UV index in September
Nassau Bay, TX

Average UV index in September - Nassau Bay, TX
  • Average UV index in September: 6

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

Average cloud cover in September
Nassau Bay, TX

Average cloud cover in September - Nassau Bay, TX
  • Average cloud cover in September: 31

The month with the most cloud cover is February (Cloud cover 52).
The month with the least cloud cover is August (Cloud cover 26).

Average visibility in September
Nassau Bay, TX

Average visibility in September - Nassau Bay, 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).

Nassau Bay, Texas, USA

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