September weather forecast
Williamsburg, FL

The first month of the autumn, September, is still a hot month in Williamsburg, Florida, with an average temperature varying between 88.5°F (31.4°C) and 74.5°F (23.6°C).

Temperature

With the onset of September, Williamsburg's average high-temperature clocks in at a still hot 88.5°F (31.4°C), showing a minor fluctuation from the previous month. In the month of September, Williamsburg witnesses a consistent average low-temperature of 74.5°F (23.6°C).

Heat index

The heat index for September is calculated to be a scorching 105.8°F (41°C). Incorporate additional safety actions, heat cramps and heat exhaustion are possible. Long-term activity may induce heatstroke.
Always consider that heat index estimations are for light winds and places in the shade. Heat index values have the potential to be boosted by 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'apparent temperature' or 'feels like', evaluates the perceived heat by adding the effect of moisture in the air. An individual's perception of weather can be swayed by a variety of elements including metabolic differences, pregnancy status, and their level of physical exertion. With direct sunlight, be aware that it might enhance the heat sensation, raising the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are quite important for children. Children usually face more risks than adults as their ability to sweat is less. Additionally, their larger skin surface in relation to their petite bodies and higher heat output due to their activities increases their vulnerability.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. Excessive heat that's not properly managed leads to increased body temperatures and resultant health issues.

Humidity

The most humid month in Williamsburg is September, with an average relative humidity of 77%.

Rainfall

In September, the rain falls for 15.4 days. Throughout September, 0.75" (19mm) of precipitation is accumulated. In Williamsburg, during the entire year, the rain falls for 126.6 days and collects up to 9.06" (230mm) of precipitation.

Daylight

In Williamsburg, the average length of the day in September is 12h and 19min.
On the first day of the month, sunrise is at 7:04 am and sunset at 7:46 pm. On the last day of September, in Williamsburg, sunrise is at 7:18 am and sunset at 7:12 pm EDT.

Sunshine

In Williamsburg, Florida, the average sunshine in September is 8.5h.

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 threat to health from unsafe exposure to UV radiation for average individuals.
Note: The UV index of 7 during September translates into the following guidance:
Beware of overexposure. Fair-skinned individuals risk burning in less than 20 minutes. The time between 10 a.m. and 4 p.m. is when UV radiation is at its peak. Limit exposure to direct sunlight during these hours. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.