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 onset of September aligns with a soft reduction in the average high-temperature, gently falling from a moderately hot 85.1°F (29.5°C) in August to a still warm 78.1°F (25.6°C). During the September nights, an average temperature of 62.2°F (16.8°C) is observed.Humidity
In Riverdale Gardens, the average relative humidity in September is 74%.Rainfall
In Riverdale Gardens, during September, the rain falls for 12.3 days and regularly aggregates up to 2.09" (53mm) of precipitation. Throughout the year, in Riverdale Gardens, there are 157.9 rainfall days, and 31.14" (791mm) of precipitation is accumulated.Snowfall
May through November are months without snowfall.Daylight
In Riverdale Gardens, the average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:37 am and sunset at 7:37 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 9.1h.UV index
In Riverdale Gardens, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for average individuals.Note: In September, the maximum UV index of 5 suggests these recommendations:
Ensure safety - Imperative it is to shield skin and eyes from damage. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Stay sun-safe with clothing that is both closely woven and worn loosely.
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 many days does it rain in September?
When it does not snow?
How many hours of daylight does Riverdale Gardens have in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Riverdale Gardens, MD
- Average high temperature in September: 78.1°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 (39.9°F).
- Average low temperature in September: 62.2°F
The month with the highest average low temperature is July (70°F).
The coldest month (with the lowest average low temperature) is January (27.7°F).
Average pressure in September
Riverdale Gardens, 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 (29.94"Hg).
Average wind speed in September
Riverdale Gardens, MD
- Average wind speed in September: 6.1mph
The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).
Average humidity in September
Riverdale Gardens, MD
- Average humidity in September: 74%
The months with the highest relative humidity are May, October and December (76%).
The months with the lowest relative humidity are April and July (71%).
Average rainfall in September
Riverdale Gardens, MD
- Average rainfall in September: 2.09"
The wettest month (with the highest rainfall) is August (3.58").
The driest month (with the least rainfall) is January (2.01").
Average rainfall days in September
Riverdale Gardens, MD
- Average rainfall days in September: 12.3 days
The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is November (9 days).
Average snowfall in September
Riverdale Gardens, MD
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.6").
The months with the least snowfall are May, June, July, August, September, October and November (0").
Average snowfall days in September
Riverdale Gardens, MD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.1 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
Riverdale Gardens, MD
- Average daylight in September: 12h and 2min
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: 9h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is February (Average sunshine: 5h and 0min).
Average sunshine days in September
Riverdale Gardens, MD
- Average sunshine days in September: 15.6 days
The month with the most sunshine days is November (19.1 days).
The month with the least sunshine days is May (11.8 days).
Average UV index in September
Riverdale Gardens, 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 and December (UV index 2).
Average cloud cover in September
Riverdale Gardens, MD
- Average cloud cover in September: 36
The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 29).
Average visibility in September
Riverdale Gardens, MD
- 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).
Riverdale Gardens, Maryland, USA
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