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
With the arrival of September, Riverdale Heights notices a mild change in the average high-temperature, sliding from August's 85.1°F (29.5°C) to a still moderately hot 78.1°F (25.6°C). Riverdale Heights experiences a mean temperature of 62.2°F (16.8°C) during September nights.Humidity
The average relative humidity in September in Riverdale Heights is 74%.Rainfall
In Riverdale Heights, Maryland, in September, during 12.3 rainfall days, 2.09" (53mm) of precipitation is typically accumulated. In Riverdale Heights, during the entire year, the rain falls for 157.9 days and collects up to 31.14" (791mm) of precipitation.Snowfall
May through November are months without snowfall.Daylight
In Riverdale Heights, the average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:37 am and sunset at 7:37 pm. On the last day of September, in Riverdale Heights, sunrise is at 7:03 am and sunset at 6:51 pm EDT.
Sunshine
In Riverdale Heights, the average sunshine in September is 9.1h.UV index
In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: The maximum UV index, 5 during September, leads to the following recommendations:
Exercise caution. Those with pale skin may experience burns in less than half an hour. Minimize direct exposure to the Sun during midday when its radiation is at its peak. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.
Frequently asked questions
What is the average September temperature in Riverdale Heights?
What is the average humidity in September in Riverdale Heights?
How much does it rain in Riverdale Heights in September?
When it does not snow in Riverdale Heights?
How many hours of daylight does Riverdale Heights have in September?
When are sunrise and sunset in September in Riverdale Heights?
How many hours of sunshine does Riverdale Heights have in September?
What is the UV index reading in September in Riverdale Heights?
Average temperature in September
Riverdale Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, 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 Heights, Maryland, USA
Weather forecast for your location
2. Allow the app to use your location
