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 commencement of September indicates a gentle shift in the average high-temperature, receding from August's tropical 88.2°F (31.2°C) to a warm 81.5°F (27.5°C). Alton registers a consistent average low-temperature of 61.9°F (16.6°C) during September.Heat index
Throughout September, the heat index is calculated to be a tropical 86°F (30°C). If one continues to be active during enduring exposure, it could result in fatigue and heat cramps.Remember that heat index calculations are made for conditions in the shade with light wind. The heat index might be elevated by 15 Fahrenheit (8 Celsius) degrees due to direct sun exposure.
Note: The heat index, also known as 'feels like' or 'felt air temperature', integrates the air's temperature and its humidity to showcase the felt temperature by people. Metabolic differences, pregnancy status, and the level of physical activity are additional factors influencing an individual's weather perception. Realize that direct exposure to sunlight can augment the felt heat, leading to a potential increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are primarily vital for children. Youngsters frequently overlook the need for breaks and fluid intake. Thirst is an advanced sign of dehydration - thereby highlighting the importance of keeping hydrated, particularly during long physical activities.
Humidity
In September, the average relative humidity in Alton is 74%.Rainfall
The month with the least rainfall is September, when the rain falls for 13 days and typically collects 1.77" (45mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
In September, the average length of the day in Alton is 12h and 24min.On the first day of the month, sunrise is at 6:47 am and sunset at 7:43 pm. On the last day of September, in Alton, Virginia, sunrise is at 7:10 am and sunset at 7:00 pm EDT.
Sunshine
In September, the average sunshine in Alton is 8.8h.UV index
In September, the average daily maximum UV index in Alton is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for the average person.Note: An average maximum UV index of 5 in September leads to these recommendations:
Take precautions - Protection against sun damage is advised. During midday, the Sun's radiation is strongest, and it's advisable to reduce direct exposure. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September in Alton?
What is the average humidity in September in Alton?
What is the driest month in Alton?
How much does it rain in Alton in September?
When it does not snow in Alton?
What is the average length of the day in September in Alton?
When are sunrise and sunset in September in Alton?
How long on average sun shines in September in Alton?
What is the UV index reading in September in Alton?
Average temperature in September
Alton, VA
- Average high temperature in September: 81.5°F
The warmest month (with the highest average high temperature) is July (90.3°F).
The month with the lowest average high temperature is January (45.5°F).
- Average low temperature in September: 61.9°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (30.4°F).
Average pressure in September
Alton, VA
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.97"Hg).
Average wind speed in September
Alton, VA
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is April (7.3mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in September
Alton, VA
- Average humidity in September: 74%
The month with the highest relative humidity is December (77%).
The month with the lowest relative humidity is July (69%).
Average rainfall in September
Alton, VA
- Average rainfall in September: 1.77"
The wettest month (with the highest rainfall) is May (2.95").
The driest month (with the least rainfall) is September (1.77").
Average rainfall days in September
Alton, VA
- Average rainfall days in September: 13 days
The months with the highest number of rainy days are May and July (17.3 days).
The month with the least rainy days is November (9.2 days).
Average snowfall in September
Alton, VA
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.48").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Alton, VA
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (3.1 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
Alton, VA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 42min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is June (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 24min).
Average sunshine days in September
Alton, VA
- Average sunshine days in September: 15.8 days
The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is May (11.8 days).
Average UV index in September
Alton, 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
Alton, VA
- Average cloud cover in September: 38
The month with the most cloud cover is March (Cloud cover 43).
The months with the least cloud cover are June and July (Cloud cover 31).
Average visibility in September
Alton, VA
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are May and September (5mi).
Alton, Virginia, USA
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