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
Roslyn Hills's transition into September involves a gentle shift in temperature, receding from a tropical 88.3°F (31.3°C) in August to a warm 81.3°F (27.4°C). An average low-temperature of 62.6°F (17°C) is expected in Roslyn Hills during September.Heat index
The heat index for September is computed to be a hot 86°F (30°C). With prolonged exposure and constant activity, one might feel exhausted and experience heat cramps.Always consider that heat index estimations are for light winds and places in the shade. The heat index values could be amplified by up to 15 Fahrenheit (8 Celsius) degrees in direct sunlight.
Note: The heat index, also known as 'apparent temperature' or 'real feel', is a value derived by merging air temperature with the humidity to convey how the climate feels. Factors such as metabolic variation, pregnancy, and physical activity play a role in one's impression of weather. Recognize that direct exposure to the sun can escalate the heat effect, potentially adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are highly critical to babies and toddlers. In general, children are more at risk than adults because they sweat less. Furthermore, the large skin surface compared to their small bodies and the high heat production due to their actions contribute to this vulnerability.
Humidity
The average relative humidity in September is 73%.Rainfall
The month with the least rainfall is September, when the rain falls for 12.5 days and typically collects 1.65" (42mm) of precipitation.Snowfall
In Roslyn Hills, snow does not fall in May through October.Daylight
In September, the average length of the day in Roslyn Hills is 12h and 25min.On the first day of the month, sunrise is at 6:41 am and sunset at 7:38 pm. On the last day of September, in Roslyn Hills, sunrise is at 7:05 am and sunset at 6:54 pm EDT.
Sunshine
In Roslyn Hills, the average sunshine in September is 8.7h.UV index
In Roslyn Hills, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.Note: An average UV index of 5 in September transforms into this advice:
Exercise caution. The susceptibility of light skin individuals to burns is less than 30 minutes. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
Frequently asked questions
What is the usual temperature for Roslyn Hills in September?
What is the average humidity in September in Roslyn Hills?
What is the driest month in Roslyn Hills?
How much does it rain in Roslyn Hills in September?
When it does not snow in Roslyn Hills?
How many hours of daylight does Roslyn Hills have in September?
When are sunrise and sunset in September in Roslyn Hills?
How long on average sun shines in September in Roslyn Hills?
What is the UV index reading in September in Roslyn Hills?
Average temperature in September
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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
Roslyn Hills, 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).
Roslyn Hills, Virginia, USA
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