September weather forecast
Bay Saint Louis, MS

September in Bay Saint Louis, Mississippi, signifies the outset of autumn. The city sees a significant decrease in temperature and humidity from the preceding month. Still, residents and visitors continue to enjoy the long daylight hours and warm sea temperatures. September records a sea temperature reduction of 3.2°F (-16°C) from August, marking the beginning of the end of the swimming season. It’s truly the transitional month of the year from summer to autumn.

Temperature

September notes an average high-temperature of a still hot 86°F (30°C), subtly differing from August's 89.2°F (31.8°C). Bay Saint Louis's nighttime temperature in September drops to an average of 74.3°F (23.5°C).

Heat index

In September, the heat index is appraised at a torrid 96.8°F (36°C). Implement enhanced safety actions, heat cramps and heat exhaustion could occur. Sustained activity might result in heatstroke.
When considering the heat index, it's pivotal to note it is for shade and mild wind conditions. Heat index values may be hiked up by 15 Fahrenheit (8 Celsius) degrees under direct sunshine.
Note: The heat index, also known as 'felt air temperature' or 'feels like', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. 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. 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 hold particular importance for children. Young children are more at risk than adults since they tend to sweat less. Moreover, their large skin surface in proportion to their small bodies and the high heat production due to their activities contribute to their vulnerability.
When faced with excessive heat, the human body begins to perspire, utilizing the cooling benefits of sweat evaporation. During high air temperature and humidity (high heat index), the process of perspiration is hindered, intensifying the sensation of heat. When body temperature rises due to excess heat gain beyond its removal capability, one might experience heat-related disorders.

Humidity

In September, the average relative humidity is 75%.

Rainfall

In Bay Saint Louis, in September, it is raining for 15.4 days, with typically 0.83" (21mm) of accumulated precipitation. In Bay Saint Louis, Mississippi, during the entire year, the rain falls for 131.5 days and collects up to 12.01" (305mm) of precipitation.

Snowfall

February through December are months without snowfall in Bay Saint Louis.

Ocean temperature

In Bay Saint Louis, in September, the average water temperature is 82.9°F (28.3°C).
Note: Swimming, diving, and other water activities in temperatures ranging from 77°F (25°C) to 84.2°F (29°C) are highly enjoyable and provide prolonged comfort without unease.

Daylight

The average length of the day in September is 12h and 20min.
On the first day of September in Bay Saint Louis, sunrise is at 6:34 am and sunset at 7:19 pm. On the last day of the month, sunrise is at 6:50 am and sunset at 6:43 pm CDT.

Sunshine

In September, the average sunshine is 10.1h.

UV index

In September, the average daily maximum UV index is 6. A UV Index value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV rays for the ordinary person.
Note: In September, the maximum UV index of 6 suggests this advice:
Take precautions against overexposure. Protection against sun damage is needed. Stay out of direct sunlight and seek shade between 10 a.m. and 4 p.m., when UV radiation is strongest, but remember that shade devices may not offer full sun protection. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.