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 snowfall in September
- Average snowfall 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
The start of September comes with a small reduction in the average high-temperature, subtly receding from a hot 88.3°F (31.3°C) in August to a moderately hot 82.2°F (27.9°C). Mountain Island's nighttime temperature in September drops to an average of 62.6°F (17°C).Heat index
The heat index value for September is appraised at a tropical 87.8°F (31°C). Exhaustion becomes probable with enduring exposure and activity, potentially causing heat cramps.Be advised, the heat index considers values for conditions in shade and with a light breeze. A rise of up to 15 Fahrenheit (8 Celsius) degrees in the heat index could result from direct sunlight.
Note: The heat index, also known as 'feels like' or 'apparent temperature', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. This effect is personal, shaped by the individual's physical activity and heat sensitivity, influenced by factors including wind, clothing, and metabolic variances. One must note that being under the direct sun can escalate the heat's effects, with the heat index possibly rising by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Young people are generally more susceptible than adults because they perspire less. Furthermore, their proportionally larger skin surface to their petite bodies and the increased heat output from their actions add to the risk.
Humidity
The average relative humidity in September is 73%.Rainfall
In Mountain Island, during September, the rain falls for 13.4 days and regularly aggregates up to 2.2" (56mm) of precipitation. In Mountain Island, during the entire year, the rain falls for 158.9 days and collects up to 31.26" (794mm) of precipitation.Snowfall
April through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 23min.On the first day of September, sunrise is at 6:56 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 7:08 pm EDT.
Sunshine
The average sunshine in September is 8.6h.UV index
The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: In September, the maximum UV index of 5 suggests this advice:
Exercise prevention - Protecting skin and eyes from harm is required. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow in Mountain Island?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Mountain Island have in September?
How high is the UV index in September in Mountain Island?
Average temperature in September
Mountain Island, NC
- Average high temperature in September: 82.2°F
The warmest month (with the highest average high temperature) is July (90.1°F).
The month with the lowest average high temperature is January (47.8°F).
- Average low temperature in September: 62.6°F
The month with the highest average low temperature is July (69.1°F).
The coldest month (with the lowest average low temperature) is January (32.5°F).
Average pressure in September
Mountain Island, NC
- Average pressure in September: 30.04"Hg
The month with the highest atmospheric pressure is November (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.98"Hg).
Average wind speed in September
Mountain Island, NC
- Average wind speed in September: 4.9mph
The windiest month (with the highest average wind speed) is April (7.2mph).
The calmest month (with the lowest average wind speed) is August (4.2mph).
Average humidity in September
Mountain Island, NC
- Average humidity in September: 73%
The month with the highest relative humidity is December (76%).
The month with the lowest relative humidity is July (70%).
Average rainfall in September
Mountain Island, NC
- Average rainfall in September: 2.2"
The wettest month (with the highest rainfall) is August (3.43").
The driest month (with the least rainfall) is October (1.93").
Average rainfall days in September
Mountain Island, NC
- Average rainfall days in September: 13.4 days
The month with the highest number of rainy days is July (18.3 days).
The month with the least rainy days is November (8.8 days).
Average snowfall in September
Mountain Island, NC
- Average snowfall in September: 0"
The month with the highest snowfall is December (2.01").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Mountain Island, NC
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (1.8 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Mountain Island, NC
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 30min).
The month with the shortest days is December (Average daylight: 9h and 48min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).
Average sunshine days in September
Mountain Island, NC
- Average sunshine days in September: 14.9 days
The month with the most sunshine days is October (20.7 days).
The month with the least sunshine days is July (10.6 days).
Average UV index in September
Mountain Island, NC
- Average UV index in September: 5
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 2).
Average cloud cover in September
Mountain Island, NC
- Average cloud cover in September: 34
The month with the most cloud cover is December (Cloud cover 43).
The months with the least cloud cover are June and July (Cloud cover 30).
Average visibility in September
Mountain Island, NC
- 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).
Mountain Island, North Carolina, USA
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