September weather forecast
Brownsville, TX

In Brownsville, September brings a gradual respite from summer heat with temperatures starting their return journey towards annual mean values. Rainfall picks up pace, accumulating to 1.81" (46mm) - the highest in the year, making the weather a mix of wet and hot sensation. A significant decrease in wind speed and pressure corresponds to the transition to the fall season. The gradual reduction in daylight hours commences as days start shrinking. Though sunshine hours drop, they still provide an ample amount of light during the day.

Temperature

With the advent of September, Brownsville experiences an average high-temperature of a still hot 89.4°F (31.9°C), mirroring a close resemblance to the previous month. Throughout September, a steady low-temperature average of 78.8°F (26°C) is noted.

Heat index

September's heat index is estimated at a scorching 104°F (40°C). Implement heightened safety measures - risk of heat exhaustion and heat cramps is increased. Prolonged activity may result in heatstroke.
Bear in mind that the heat index values are determined for shaded areas and light breezes. With exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', quantifies the warmth felt when relative humidity is considered. The individual's experience of temperature can be shaped by numerous aspects such as metabolic variations, physical exertion, and attire. Consider the fact that direct sun exposure can influence how hot one feels, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. 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.
To combat high temperatures, the human body perspires and relies on sweat evaporation for cooling. Heightened relative humidity interferes with the body's usual cooling mechanism by reducing evaporation, subsequently decreasing the body's cooling rate and increasing the sensation of heat. If heat absorption exceeds the body's cooling ability, body temperature can elevate, resulting in potential thermal illnesses.

Humidity

In September, the average relative humidity is 70%.

Rainfall

The month with the most rainfall is September, when the rain falls for 14.4 days and typically aggregates up to 1.81" (46mm) of precipitation.

Daylight

The average length of the day in September is 12h and 17min.
On the first day of September in Brownsville, sunrise is at 7:10 am and sunset at 7:49 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 7:17 pm CDT.

Sunshine

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

UV index

In Brownsville, the average daily maximum UV index in September is 7. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for average individuals.
Note: In September, a daily UV index of 7 turns into the following recommendations:
Continue precautions and advocate sun safety advice. Deterrence of sunburn is indispensable. Stay in the shade and limit sun exposure from 10 a.m. to 4 p.m., when UV radiation is most potent. Keep in mind that shade structures like parasols or canopies do not offer full protection. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage.