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
In Dumbarton, entering September brings a subtle temperature decrement, reducing from August's tropical 88.3°F (31.3°C) to a warm 81.3°F (27.4°C). Throughout September, the temperature in Dumbarton tends to fall to a consistent average low of 62.6°F (17°C).Heat index
During September, the heat index is evaluated at a hot 86°F (30°C). Prolonged exposure and physical activity might induce exhaustion, potentially causing heat cramps.Heat index determinations are made taking into account the shade and light air movements. Direct sunlight might cause an increase of up to 15 Fahrenheit (8 Celsius) degrees in the heat index.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', embodies the combination of air temperature and moisture content to illustrate perceived heat. Additional factors encompassing metabolic differences, the level of physical activity, and clothing can impact the individual's perception of temperature. Direct exposure to sun rays can potentially augment the heat sensation, elevating the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical to babies and toddlers. Younglings are generally more in peril than adults due to their reduced perspiration. Coupled with a larger skin surface relative to their tiny bodies and greater heat production because of their activity, they become more at risk.
Humidity
In September, the average relative humidity is 73%.Rainfall
September is the month with the least rainfall. Rain falls for 12.5 days and accumulates 1.65" (42mm) of precipitation.Snowfall
In Dumbarton, snow does not fall in May through October.Daylight
In Dumbarton, the average length of the day in September is 12h and 25min.On the first day of September, sunrise is at 6:40 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:54 pm EDT.
Sunshine
The average sunshine in September is 8.7h.UV index
In Dumbarton, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: The UV index of 5 in September translates into these instructions:
Safety measures are advised. Light-skinned individuals may experience burns in under half an hour. The solar radiation around mid-day is intense; avoid the Sun and stay safe. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
What is the driest month?
How much does it rain in September?
When it does not snow?
How many hours of daylight does Dumbarton have in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Dumbarton have in September?
What is the UV index reading in September?
Average temperature in September
Dumbarton, VA
- Average high temperature in September: 81.3°F
The warmest month (with the highest average high temperature) is July (90.7°F).
The month with the lowest average high temperature is January (44.2°F).
- Average low temperature in September: 62.6°F
The month with the highest average low temperature is July (69.6°F).
The coldest month (with the lowest average low temperature) is January (29.5°F).
Average pressure in September
Dumbarton, VA
- Average pressure in September: 30.04"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in September
Dumbarton, VA
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is April (7.4mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in September
Dumbarton, VA
- Average humidity in September: 73%
The month with the highest relative humidity is December (78%).
The month with the lowest relative humidity is July (68%).
Average rainfall in September
Dumbarton, VA
- Average rainfall in September: 1.65"
The wettest month (with the highest rainfall) is August (2.72").
The driest month (with the least rainfall) is September (1.65").
Average rainfall days in September
Dumbarton, VA
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is November (8.8 days).
Average snowfall in September
Dumbarton, VA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.77").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Dumbarton, VA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (3.5 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Dumbarton, VA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is December (Average sunshine: 5h and 12min).
Average sunshine days in September
Dumbarton, VA
- Average sunshine days in September: 15.8 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is May (11.9 days).
Average UV index in September
Dumbarton, VA
- Average UV index in September: 5
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in September
Dumbarton, VA
- Average cloud cover in September: 39
The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in September
Dumbarton, VA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).
Dumbarton, Virginia, USA
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