September weather forecast
Saint Petersburg, FL

September in Saint Petersburg, Florida, witnesses the onset of a transition, marked by a subtle decrease in temperatures from August. A downward trend in daylight hours and sea temperatures accentuate the changing season from summer to autumn. Conversely, the UV Index remains constant at seven, shedding an alluring light that is unique to this period. With a rainfall drop to 3.46in, September's weather turns noticeably drier, launching into the fall season. Acknowledging the falling temperatures, the wind begins to pick up slightly, adding a refreshing change after hot summer.

Temperature

Saint Petersburg's weather in September displays an average high-temperature of a still tropical 87.3°F (30.7°C), showing minor disparity from August's 88.7°F (31.5°C). Saint Petersburg's temperature in September lowers to a consistent average of 77.2°F (25.1°C) during the nights.

Heat index

The heat index value for September is appraised at a very hot 100.4°F (38°C). Adopt heightened preventive measures, heat exhaustion and heat cramps are probable. Persistent activity could lead to heatstroke.
Heat index data is primarily for areas with shade and subjected to light winds. Being under direct sunlight might amplify the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', is an indicator that blends the effects of temperature and humidity to depict perceived warmth. 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 sun's direct rays and their impact; they can potentially increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely vital to babies and toddlers. Young individuals usually face greater risks than adults as their sweat production is less. Also, their larger skin surface relative to their small bodies and the high heat generation due to their activity contributes to their vulnerability.
The human body normally cools itself by perspiration. Excessive warmth is eliminated from the body by evaporation of sweat. With a high level of moisture in the air, the evaporation process becomes less efficient, preventing the body from cooling down efficiently and resulting in a sensation of overheating. When heat uptake goes beyond the body's cooling mechanisms, there's a surge in body temperature, posing health risks.

Humidity

In Saint Petersburg, the average relative humidity in September is 74%.

Rainfall

In Saint Petersburg, during September, the rain falls for 21.7 days and regularly aggregates up to 3.46" (88mm) of precipitation. In Saint Petersburg, during the entire year, the rain falls for 172.1 days and collects up to 27.2" (691mm) of precipitation.

Ocean temperature

In Saint Petersburg, the average seawater temperature in September is 84.7°F (29.3°C).
Note: Engaging in water activities, such as swimming or diving, in temperatures from 77°F (25°C) to 84.2°F (29°C) is very pleasurable for extended periods, without any discomfort.

Daylight

In Saint Petersburg, the average length of the day in September is 12h and 19min.
On the first day of September, sunrise is at 7:09 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 7:17 pm EDT.

Sunshine

In Saint Petersburg, the average sunshine in September is 9.1h.

UV index

May through September, with an average maximum UV index of 7, are months with the highest UV index. A UV Index of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to Sun's UV rays for the average person.
Note: In September, a daily UV index of 7 turns into the following recommendations:
Avoid overexposure. Fair-skinned individuals can burn in under 20 minutes. Between 10 a.m. and 4 p.m., the Sun emits the most powerful UV radiation. Limit direct exposure to the Sun during these hours. Opt for tightly woven and loose clothing to enhance protection from the Sun. Caution! The Sun's UV rays become stronger due to reflections from water and sand.