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
Stepping into September, Riverdale observes a temperature decline, with the average high falling from August's warm 81.1°F (27.3°C) to an agreeable 70.7°F (21.5°C). Riverdale's nighttime temperature in September drops to an average of 51.3°F (10.7°C).Humidity
In September, the average relative humidity is 56%.Rainfall
In September, the rain falls for 9 days. Throughout September, 2.05" (52mm) of precipitation is accumulated. Throughout the year, there are 95.9 rainfall days, and 14.65" (372mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall in Riverdale.Daylight
In September, the average length of the day is 12h and 33min.On the first day of the month, sunrise is at 7:05 am and sunset at 8:25 pm. On the last day of September, sunrise is at 7:44 am and sunset at 7:26 pm CDT.
Sunshine
The average sunshine in September is 8.6h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: A daily high UV index of 4 in September leads to these guidelines:
Put precautions into practice - Ensuring skin and eye safety is a necessity. During midday, the Sun's radiation is strongest, and it's advisable to reduce direct exposure. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
How high is the UV index in September in Riverdale?
Average temperature in September
Riverdale, ND
- Average high temperature in September: 70.7°F
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (19.6°F).
- Average low temperature in September: 51.3°F
The month with the highest average low temperature is July (59.7°F).
The coldest month (with the lowest average low temperature) is January (5.4°F).
Average pressure in September
Riverdale, ND
- Average pressure in September: 29.94"Hg
The month with the highest atmospheric pressure is February (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).
Average wind speed in September
Riverdale, ND
- Average wind speed in September: 10mph
The windiest month (with the highest average wind speed) is October (11mph).
The calmest month (with the lowest average wind speed) is August (8.6mph).
Average humidity in September
Riverdale, ND
- Average humidity in September: 56%
The month with the highest relative humidity is January (90%).
The month with the lowest relative humidity is August (54%).
Average rainfall in September
Riverdale, ND
- Average rainfall in September: 2.05"
The wettest month (with the highest rainfall) is June (2.64").
The driest month (with the least rainfall) is February (0.39").
Average rainfall days in September
Riverdale, ND
- Average rainfall days in September: 9 days
The month with the highest number of rainy days is June (13.9 days).
The month with the least rainy days is February (2.1 days).
Average snowfall in September
Riverdale, ND
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.31").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Riverdale, ND
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (13 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Riverdale, ND
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is July (Average sunshine: 11h and 18min).
The months with the least sunshine are January and December (Average sunshine: 3h and 42min).
Average sunshine days in September
Riverdale, ND
- Average sunshine days in September: 19.8 days
The month with the most sunshine days is September (19.8 days).
The month with the least sunshine days is March (13.9 days).
Average UV index in September
Riverdale, ND
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February and December (UV index 1).
Average cloud cover in September
Riverdale, ND
- Average cloud cover in September: 26
The month with the most cloud cover is February (Cloud cover 63).
The months with the least cloud cover are July and August (Cloud cover 22).
Average visibility in September
Riverdale, ND
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February, March and December (5mi).
Riverdale, North Dakota, USA
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