September weather forecastStephen Knolls, MD
September
Weather in September
September, the first month of the autumn in Stephen Knolls, is still a warm month, with an average temperature varying between 78.4°F (25.8°C) and 61.7°F (16.5°C).Temperature
With the beginning of September, the average high-temperature shows a small decrease, transitioning from a moderately hot 85.6°F (29.8°C) in August to a still warm 78.4°F (25.8°C). An average low-temperature of 61.7°F (16.5°C) is observed during September nights.Humidity
In September, the average relative humidity is 73%.Rainfall
In Stephen Knolls, during September, the rain falls for 12.4 days and regularly aggregates up to 2.2" (56mm) of precipitation. In Stephen Knolls, Maryland, during the entire year, the rain falls for 154.8 days and collects up to 30.28" (769mm) of precipitation.Snowfall
In Stephen Knolls, snow does not fall in May through October.Daylight
In September, the average length of the day is 12h and 26min.On the first day of September in Stephen Knolls, sunrise is at 6:37 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:51 pm EDT.
Sunshine
The average sunshine in September is 8.7h.UV index
In Stephen Knolls, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum daily UV index of 5 in September converts into the following recommendations:
Exercise prevention - Warding off sunburn is urged. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Stephen Knolls, MD
- Average high temperature in September: 78.4°F
The warmest month (with the highest average high temperature) is July (87.4°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in September: 61.7°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 (27.1°F).
Average pressure in September
Stephen Knolls, MD
- Average pressure in September: 30.05"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
Stephen Knolls, MD
- Average wind speed in September: 5.8mph
The windiest month (with the highest average wind speed) is March (8.1mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in September
Stephen Knolls, MD
- Average humidity in September: 73%
The months with the highest relative humidity are May, October and December (75%).
The month with the lowest relative humidity is July (69%).
Average rainfall in September
Stephen Knolls, MD
- Average rainfall in September: 2.2"
The wettest month (with the highest rainfall) is August (3.86").
The driest month (with the least rainfall) is January (1.89").
Average rainfall days in September
Stephen Knolls, MD
- Average rainfall days in September: 12.4 days
The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is November (8.5 days).
Average snowfall in September
Stephen Knolls, MD
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.87").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Stephen Knolls, MD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.6 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
Stephen Knolls, MD
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 8h and 42min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 54min).
Average sunshine days in September
Stephen Knolls, MD
- Average sunshine days in September: 16.1 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is May (12 days).
Average UV index in September
Stephen Knolls, MD
- 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, November and December (UV index 2).
Average cloud cover in September
Stephen Knolls, MD
- Average cloud cover in September: 38
The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 32).
Average visibility in September
Stephen Knolls, MD
- 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).
