September weather forecastJohns Island, SC
September
Weather in September
September, the first month of the autumn in Johns Island, is still a warm month, with an average temperature ranging between min 72°F (22.2°C) and max 84.4°F (29.1°C).Temperature
As September unfolds, the average high-temperature reaches a warm 84.4°F (29.1°C), hinting at a slight fluctuation from the previous month. In September, the recorded average low-temperature is a pleasant 72°F (22.2°C).Heat index
September's mean heat index is appraised at a hot 93.2°F (34°C). Exercise extra preventive actions, heat cramps and heat exhaustion are plausible. Continuous activity could result in heatstroke.Know that the heat index computations account for shaded terrains and slight winds. Direct sunlight exposure may cause a 15 Fahrenheit (8 Celsius) degrees rise in the heat index.
Note: The heat index, also known as 'real feel' or 'apparent temperature', reflects the feeling of heat when considering both air temperature and humidity. The influence of weather is personal, with varied individuals experiencing it differently due to differences in body mass, stature, and physical exertion levels. Being under direct sunshine can magnify the heat experience, possibly pushing up the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely vital to babies and toddlers. Kids frequently ignore the importance of taking a break and rehydrating. Thirst is a late symptom of dehydration - thus, it is crucial to stay hydrated, especially during long-lasting physical activities.
Humidity
In Johns Island, the average relative humidity in September is 75%.Rainfall
In Johns Island, during September, the rain falls for 14.8 days and regularly aggregates up to 2.76" (70mm) of precipitation. In Johns Island, South Carolina, during the entire year, the rain falls for 154.4 days and collects up to 23.43" (595mm) of precipitation.Snowfall
March through November are months without snowfall.Daylight
The average length of the day in September in Johns Island, South Carolina, is 12h and 22min.On the first day of the month, sunrise is at 6:55 am and sunset at 7:44 pm. On the last day of September, sunrise is at 7:14 am and sunset at 7:05 pm EDT.
Sunshine
The average sunshine in September in Johns Island is 9h.UV index
The average daily maximum UV index in September in Johns Island is 6. A UV Index value of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV rays for ordinary individuals.Note: In September, a daily maximum UV index of 6 leads to the following instructions:
Conform to measures and uphold sun safety traditions. Warding off skin and eye harm is necessary. Be aware that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. and try to reduce direct sun exposure during this period as much as possible. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Johns Island, SC
- Average high temperature in September: 84.4°F
The warmest month (with the highest average high temperature) is July (89.6°F).
The month with the lowest average high temperature is January (56.8°F).
- Average low temperature in September: 72°F
The month with the highest average low temperature is July (76.5°F).
The coldest month (with the lowest average low temperature) is January (42.8°F).
Average pressure in September
Johns Island, SC
- Average pressure in September: 30"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.98"Hg).
Average wind speed in September
Johns Island, SC
- Average wind speed in September: 7.1mph
The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in September
Johns Island, SC
- Average humidity in September: 75%
The month with the highest relative humidity is December (77%).
The month with the lowest relative humidity is March (72%).
Average rainfall in September
Johns Island, SC
- Average rainfall in September: 2.76"
The wettest month (with the highest rainfall) is August (4.29").
The driest month (with the least rainfall) is January (0.67").
Average rainfall days in September
Johns Island, SC
- Average rainfall days in September: 14.8 days
The month with the highest number of rainy days is August (22.7 days).
The month with the least rainy days is November (6.9 days).
Average snowfall days in September
Johns Island, SC
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (0.3 days).
The months with the least snowfall days are March, April, May, June, July, August, September, October and November (0 days).
Average daylight in September /
Average sunshine in September
Johns Island, SC
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in September: 9h and 0min
The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 36min).
Average sunshine days in September
Johns Island, SC
- Average sunshine days in September: 11 days
The month with the most sunshine days is November (20.4 days).
The month with the least sunshine days is August (6.1 days).
Average UV index in September
Johns Island, SC
- Average UV index in September: 6
The months with the highest UV index are May, June, July and August (UV index 7).
The month with the lowest UV index is January (UV index 3).
Average cloud cover in September
Johns Island, SC
- Average cloud cover in September: 30
The month with the most cloud cover is December (Cloud cover 40).
The months with the least cloud cover are June and July (Cloud cover 26).
Average visibility in September
Johns Island, SC
- 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).
