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
Frederiksted witnesses its highest temperatures in September and October, reaching an average of 84.2°F (29°C).Heat index
September's heat index is calculated to be a hot 93.2°F (34°C). Special measures are necessary to avoid heat cramps and heat exhaustion. Persistent activity could result in heatstroke.The metrics for the heat index are tailored for both shady environments and light winds. Direct sunshine exposure could raise heat index values by as much as 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'feels like', represents the fusion of temperature and moisture in the air to suggest how warm it feels. This effect is personal, influenced by the individual's physical activity and heat sensitivity, shaped by factors including wind, attire, and metabolic variations. When directly under the sun, the weather's impact can intensify, possibly boosting the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Typically, young kids are at a higher risk than adults since they sweat less. Also, the larger skin surface in proportion to their small bodies and the heightened heat production due to their active nature adds to their vulnerability.
Humidity
The average relative humidity in September is 76%.Rainfall
In September, the rain falls for 22.8 days. Throughout September, 4.09" (104mm) of precipitation is accumulated. In Frederiksted, during the entire year, the rain falls for 254.5 days and collects up to 29.49" (749mm) of precipitation.Daylight
In Frederiksted, the average length of the day in September is 12h and 14min.On the first day of the month, sunrise is at 6:05 am and sunset at 6:33 pm. On the last day of September, sunrise is at 6:09 am and sunset at 6:08 pm AST.
Sunshine
In Frederiksted, the average sunshine in September is 8.9h.UV index
January through December, with an average maximum UV index of 7, are months with the highest UV index. The months with the lowest UV index are January through December, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV rays for average individuals.Note: In September, the UV index of 7 transforms into the following advice:
Continue precautions and advocate sun safety advice. Deterrence of sunburn is indispensable. Seek shade and limit direct Sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its peak, but be aware that not all shade structures provide complete sun protection. Experience reduced UV exposure by about half when donning a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What part of the year is the hottest?
How hot is it in September?
What is the average humidity in September?
How much does it rain in September?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Frederiksted have in September?
What are the months with the highest UV index?
When is the lowest UV index in Frederiksted?
What is the UV index reading in September?
Average temperature in September
Frederiksted, VI
- Average high temperature in September: 84.2°F
The warmest months (with the highest average high temperature) are September and October (84.2°F).
The month with the lowest average high temperature is March (78.8°F).
- Average low temperature in September: 81.9°F
The month with the highest average low temperature is October (82.2°F).
The coldest month (with the lowest average low temperature) is March (76.6°F).
Average pressure in September
Frederiksted, VI
- Average pressure in September: 29.92"Hg
The months with the highest atmospheric pressure are January, February and June (30.01"Hg).
The months with the lowest atmospheric pressure are October and November (29.9"Hg).
Average wind speed in September
Frederiksted, VI
- Average wind speed in September: 11.3mph
The windiest month (with the highest average wind speed) is July (14.7mph).
The calmest month (with the lowest average wind speed) is October (11mph).
Average humidity in September
Frederiksted, VI
- Average humidity in September: 76%
The months with the highest relative humidity are May, June, July and August (78%).
The months with the lowest relative humidity are January, February, March and December (75%).
Average rainfall in September
Frederiksted, VI
- Average rainfall in September: 4.09"
The wettest month (with the highest rainfall) is August (4.17").
The driest month (with the least rainfall) is February (1.18").
Average rainfall days in September
Frederiksted, VI
- Average rainfall days in September: 22.8 days
The month with the highest number of rainy days is August (24.7 days).
The month with the least rainy days is February (16.7 days).
Average daylight in September /
Average sunshine in September
Frederiksted, VI
- Average daylight in September: 12h and 1min
The month with the longest days is June (Average daylight: 13h and 12min).
The month with the shortest days is December (Average daylight: 11h and 6min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is December (Average sunshine: 6h and 24min).
Average sunshine days in September
Frederiksted, VI
- Average sunshine days in September: 3.7 days
The month with the most sunshine days is March (7.6 days).
The month with the least sunshine days is August (1.8 days).
Average UV index in September
Frederiksted, VI
- Average UV index in September: 7
The months with the highest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 7).
The months with the lowest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 7).
Average cloud cover in September
Frederiksted, VI
- Average cloud cover in September: 35
The months with the most cloud cover are May and July (Cloud cover 40).
The month with the least cloud cover is February (Cloud cover 33).
Average visibility in September
Frederiksted, VI
- 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).
Frederiksted, United States Virgin Islands, USA
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