September weather forecast
South Padre Island, TX

September in South Padre Island signals the advent of Autumn, thus a mild moderation of temperature. As August concludes and fall advances, the decrease in both sea and daily temperatures is experienced. A significant increase in precipitation occurs, reaching a record high of 4.13" (105mm) for the year. Despite the rain, there is ample sunshine for outdoor activities, enjoying 9 hours of sunlight per day. The season change brings about a decrease in atmospheric pressure, resulting in a comfortable breeze with 10.9mph (17.5km/h) average speed.

Temperature

September's arrival registers an average high-temperature of a still hot 86.2°F (30.1°C), closely aligning with the temperature of the previous month. South Padre Island notes a steady average temperature of 80.4°F (26.9°C) during the nights of September.

Heat index

The average heat index in September is estimated at a torrid 96.8°F (36°C). Implement more preventive measures, heat cramps and heat exhaustion are probable. Heatstroke might result from extended activity.
Bear in mind that the heat index values are determined for shaded areas and light breezes. Heat index values might soar by up to 15 Fahrenheit (8 Celsius) degrees with exposure to direct sunshine.
Note: The heat index, also known as 'feels like' or 'apparent temperature', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. The effect of weather is individual, with a variety of people experiencing it differently due to distinctions in body mass, height, and level of activity. Given the impact of direct sunlight, it's noteworthy that the felt temperature can rise by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Children often fail to understand the importance of rest and rehydration. Thirst is a late manifestation of dehydration - hence, it is crucial to stay hydrated, especially during ongoing physical activities.
The physiological response of the human body to excess warmth is to perspire, thereby cooling itself through sweat evaporation. Relative humidity in excess curtails evaporation, therefore reducing heat dissipation from the body, leading to feelings of excess heat. Excessive heat gain, when not shed effectively by the body, can result in increasing body temperatures and related hazards.

Humidity

In South Padre Island, the average relative humidity in September is 74%.

Rainfall

The month with the most rainfall is September, when the rain falls for 19.8 days and typically aggregates up to 4.13" (105mm) of precipitation.

Ocean temperature

In South Padre Island, the average seawater temperature in September is 84.6°F (29.2°C).
Note: For activities such as swimming and diving, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as particularly pleasant and satisfying for prolonged periods without feeling uneasy.

Daylight

The average length of the day in September is 12h and 18min.
On the first day of the month, sunrise is at 7:09 am and sunset at 7:47 pm. On the last day of September, in South Padre Island, sunrise is at 7:20 am and sunset at 7:15 pm CDT.

Sunshine

In September, the average sunshine is 9h.

UV index

The months with the highest UV index are April through September, with an average maximum UV index of 7. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV rays for the ordinary person.
Note: An average maximum UV index of 7 in September leads to these recommendations:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. 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. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes. Caution! The Sun's UV rays become stronger due to reflections from water and sand.