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
Riverside's September weather shows a moderate shift in high-temperatures, falling from August's agreeable 71.4°F (21.9°C) to a refreshing 61.9°F (16.6°C). Contrary to the day's heat, an average low-temperature of 37.6°F (3.1°C) is recorded during the nights in September in Riverside.Humidity
In September, the average relative humidity is 57%.Rainfall
In Riverside, in September, during 10.5 rainfall days, 1.57" (40mm) of precipitation is typically accumulated. In Riverside, during the entire year, the rain falls for 109.2 days and collects up to 23.15" (588mm) of precipitation.Snowfall
January through July, September through December are months with snowfall. September is the first month it typically snows in Riverside. Throughout September, in the average 2.4 snowfall days, it receives 3.27" (83mm) of snow. Throughout the year, there are 159.3 snowfall days, and 120.47" (3060mm) of snow is accumulated.Daylight
In Riverside, the average length of the day in September is 12h and 30min.On the first day of the month, sunrise is at 6:47 am and sunset at 8:00 pm. On the last day of September, sunrise is at 7:21 am and sunset at 7:06 pm MDT.
Sunshine
The average sunshine in September is 9.8h.UV index
The average daily maximum UV index in September is 2. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for the ordinary person.Note: The maximum UV index, 2 during September, leads to the following recommendations:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the average humidity in September?
How many days does it rain in September?
When does it start snowing?
What is the average length of the day in September?
What time are sunrise and sunset in September in Riverside?
How many hours of sunshine does Riverside have in September?
What is the UV index intensity in September?
Average temperature in September
Riverside, MT
- Average high temperature in September: 61.9°F
The warmest month (with the highest average high temperature) is July (72.9°F).
The month with the lowest average high temperature is December (20.1°F).
- Average low temperature in September: 37.6°F
The month with the highest average low temperature is August (43.7°F).
The coldest month (with the lowest average low temperature) is December (4.8°F).
Average pressure in September
Riverside, MT
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.24"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Riverside, MT
- Average wind speed in September: 6mph
The windiest month (with the highest average wind speed) is June (6.8mph).
The calmest month (with the lowest average wind speed) is August (5.8mph).
Average humidity in September
Riverside, MT
- Average humidity in September: 57%
The month with the highest relative humidity is February (95%).
The month with the lowest relative humidity is August (50%).
Average rainfall in September
Riverside, MT
- Average rainfall in September: 1.57"
The wettest month (with the highest rainfall) is May (2.8").
The driest month (with the least rainfall) is July (0.91").
Average rainfall days in September
Riverside, MT
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (2.2 days).
Average snowfall in September
Riverside, MT
- Average snowfall in September: 3.27"
The month with the highest snowfall is February (17.83").
The month with the least snowfall is August (0").
Average snowfall days in September
Riverside, MT
- Average snowfall days in September: 2.4 days
The month with the highest number of snowfall days is March (24.4 days).
The months with the least snowfall days are July and August (0.2 days).
Average daylight in September /
Average sunshine in September
Riverside, MT
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in September: 9h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 48min).
The months with the least sunshine are January, February and December (Average sunshine: 3h and 18min).
Average sunshine days in September
Riverside, MT
- Average sunshine days in September: 14.7 days
The months with the most sunshine days are July and September (14.7 days).
The month with the least sunshine days is February (5.3 days).
Average UV index in September
Riverside, MT
- Average UV index in September: 2
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 1).
Average cloud cover in September
Riverside, MT
- Average cloud cover in September: 22
The month with the most cloud cover is February (Cloud cover 76).
The month with the least cloud cover is July (Cloud cover 16).
Average visibility in September
Riverside, MT
- Average visibility in September: 6mi
The months with the highest visibility are June, July, August and September (6mi).
The months with the lowest visibility are January, February, March and December (3mi).
Riverside, Montana, USA
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