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 transition from August to September introduces an average high-temperature of a still tropical 87.3°F (30.7°C), marking an insignificant variation from the 88.7°F (31.5°C). Saint Petersburg reports a consistent average low-temperature of 77.2°F (25.1°C) throughout September nights.

Heat index

For most parts of September, the heat index is evaluated at a very hot 100.4°F (38°C). Undertake additional safety actions, risk of heat cramps and heat exhaustion is significant. Persistent activity may induce heatstroke.
Know that the heat index computations account for shaded terrains and slight winds. The heat index could see an increase by 15 Fahrenheit (8 Celsius) degrees under direct sunshine.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. The experience of temperature can be subjective, varying based on the individual's activity and heat perception, influenced by factors like wind, attire, and metabolic variations. Being aware that direct sunlight can impact the felt heat might mean an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Children regularly disregard the necessity to rest and replenish fluids. Thirst is a late symptom of dehydration - thus, maintaining hydration, particularly during long-lasting physical activities, is essential.
Evaporating sweat is a key way the human body dispels excessive warmth, all thanks to the process of perspiration. In conditions of both high temperature and humidity (a high heat index), sweating is limited and the perception of heat is enhanced. With body temperatures on the rise, inefficient heat shedding can lead to dehydration and its associated complications.

Humidity

In September, the average relative humidity is 74%.

Rainfall

In Saint Petersburg, Florida, in September, it is raining for 21.7 days, with typically 3.46" (88mm) of accumulated precipitation. Throughout the year, in Saint Petersburg, there are 172.1 rainfall days, and 27.2" (691mm) of precipitation is accumulated.

Ocean temperature

In Saint Petersburg, the average seawater temperature in September is 84.7°F (29.3°C).
Note: For swimming, diving, and enjoying other water activities, the range of 77°F (25°C) to 84.2°F (29°C) in water temperature is considered ideal, offering pleasure for extended periods without discomfort.

Daylight

In Saint Petersburg, Florida, the average length of the day in September is 12h and 19min.
On the first day of September in Saint Petersburg, Florida, 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 September, the average sunshine in Saint Petersburg 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 estimate of 6 to 7 represents a high health risk from unsafe exposure to UV radiation for average individuals.
Note: A maximum high UV index of 7 in September translates into the following recommendations:
Continue precautions and advocate sun safety advice. Deterrence of sunburn is indispensable. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Attention! The reflection of both water and sand can increase the intensity of UV rays.