Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
Port Saint John, Florida, observes an average high-temperature of a still tropical 86.4°F (30.2°C) in September, barely different from 88.7°F (31.5°C) in August. Port Saint John, during September nights, observes an average temperature of 76.6°F (24.8°C).Heat index
The heat index value for September is estimated at a very hot 100.4°F (38°C). Adopt special protective actions against heat exhaustion and heat cramps. Long-duration activity risks heatstroke.Metrics for the heat index primarily focus on shaded spots and light wind conditions. 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 'apparent temperature' or 'real feel', takes into account both air temperature and humidity to illustrate what people actually feel. Elements such as metabolic variations, being pregnant, and physical activity can impact one's weather perception. 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 remain especially vital for babies and toddlers. In general, children are more at risk than adults because they sweat less. Furthermore, the large skin surface compared to their small bodies and the high heat production due to their actions contribute to this vulnerability.
One way the human body deals with excessive warmth is by perspiring and allowing sweat to evaporate. During conditions of high air temperature and humidity (high heat index), the body's ability to perspire is inhibited, increasing the sensation of warmth. Accumulating more heat than the body can dissipate leads to an uptick in body temperature, with potential heat stress consequences.
Humidity
The average relative humidity in September is 78%.Rainfall
In Port Saint John, during September, the rain falls for 23.8 days and regularly aggregates up to 5.2" (132mm) of precipitation. In Port Saint John, during the entire year, the rain falls for 202 days and collects up to 40.2" (1021mm) of precipitation.Daylight
In Port Saint John, the average length of the day in September is 12h and 19min.On the first day of the month, sunrise is at 7:01 am and sunset at 7:44 pm. On the last day of September, sunrise is at 7:15 am and sunset at 7:09 pm EDT.
Sunshine
In September, the average sunshine is 8.9h.UV index
May through September, with an average maximum UV index of 7, are months with the highest UV index. A UV Index reading of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: In September, the maximum UV index of 7 suggests this advice:
Continue precautions and advocate sun safety advice. Deterrence of sunburn is indispensable. Avoid direct Sun exposure from 10 a.m. to 4 p.m., a period when UV radiation is most intense, and remember that not all shade structures provide full protection. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is September?
What is the average humidity in September?
How many days does it rain in September?
How many hours of daylight does Port Saint John have in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the month with the highest UV index?
What is the UV index reading in September?
Average temperature in September
Port Saint John, FL
- Average high temperature in September: 86.4°F
The warmest month (with the highest average high temperature) is August (88.7°F).
The month with the lowest average high temperature is January (68.4°F).
- Average low temperature in September: 76.6°F
The month with the highest average low temperature is August (77.9°F).
The coldest month (with the lowest average low temperature) is January (56.1°F).
Average pressure in September
Port Saint John, FL
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.97"Hg).
Average wind speed in September
Port Saint John, FL
- Average wind speed in September: 6.9mph
The windiest months (with the highest average wind speed) are January and November (8.8mph).
The calmest month (with the lowest average wind speed) is July (6mph).
Average humidity in September
Port Saint John, FL
- Average humidity in September: 78%
The month with the highest relative humidity is August (79%).
The month with the lowest relative humidity is March (71%).
Average rainfall in September
Port Saint John, FL
- Average rainfall in September: 5.2"
The wettest month (with the highest rainfall) is August (6.81").
The driest month (with the least rainfall) is March (1.42").
Average rainfall days in September
Port Saint John, FL
- Average rainfall days in September: 23.8 days
The months with the highest number of rainy days are July and August (25.8 days).
The month with the least rainy days is February (10.8 days).
Average daylight in September /
Average sunshine in September
Port Saint John, FL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 13h and 54min).
The month with the shortest days is December (Average daylight: 10h and 24min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 0min).
The months with the least sunshine are January, November and December (Average sunshine: 6h and 6min).
Average sunshine days in September
Port Saint John, FL
- Average sunshine days in September: 4.4 days
The months with the most sunshine days are January and March (17.2 days).
The month with the least sunshine days is August (2.3 days).
Average UV index in September
Port Saint John, FL
- Average UV index in September: 7
The months with the highest UV index are May, June, July, August and September (UV index 7).
The month with the lowest UV index is January (UV index 4).
Average cloud cover in September
Port Saint John, FL
- Average cloud cover in September: 29
The months with the most cloud cover are January, November and December (Cloud cover 35).
The month with the least cloud cover is May (Cloud cover 26).
Average visibility in September
Port Saint John, FL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Port Saint John, Florida, USA
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