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 September's arrival, Westby sees a decrease in average high-temperatures, moving from a moderately hot 81.3°F (27.4°C) in August to an agreeable 70°F (21.1°C). In Westby, the average nighttime temperature during September is a fresh 52.3°F (11.3°C).Humidity
In Westby, the average relative humidity in September is 50%.Rainfall
In September, the rain falls for 8.6 days. Throughout September, 1.5" (38mm) of precipitation is accumulated. In Westby, during the entire year, the rain falls for 93.3 days and collects up to 12.01" (305mm) of precipitation.Snowfall
In Westby, snow does not fall in June through September.Daylight
In Westby, the average length of the day in September is 12h and 34min.On the first day of September in Westby, Montana, sunrise is at 7:14 am and sunset at 8:37 pm. On the last day of the month, sunrise is at 7:55 am and sunset at 7:36 pm CDT.
Sunshine
The average sunshine in September is 9.9h.UV index
In Westby, 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 the ordinary person.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. Exposing oneself to the midday Sun can be harmful due to the strong UV radiation; limit your time outside. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature in Westby?
What is the average humidity in September in Westby?
How much does it rain in Westby in September?
When it does not snow in Westby?
Does it snow in Westby in September?
What is the average length of the day in September in Westby?
When are sunrise and sunset in September in Westby?
How many hours of sunshine does Westby have in September?
What is the UV index intensity in September in Westby?
Average temperature in September
Westby, MT
- Average high temperature in September: 70°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is February (19.8°F).
- Average low temperature in September: 52.3°F
The month with the highest average low temperature is July (61°F).
The coldest month (with the lowest average low temperature) is February (6.3°F).
Average pressure in September
Westby, MT
- Average pressure in September: 29.93"Hg
The month with the highest atmospheric pressure is February (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.83"Hg).
Average wind speed in September
Westby, MT
- Average wind speed in September: 10.2mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is February (9.2mph).
Average humidity in September
Westby, MT
- Average humidity in September: 50%
The months with the highest relative humidity are January and February (88%).
The month with the lowest relative humidity is August (46%).
Average rainfall in September
Westby, MT
- Average rainfall in September: 1.5"
The wettest month (with the highest rainfall) is June (2.17").
The driest month (with the least rainfall) is February (0.47").
Average rainfall days in September
Westby, MT
- Average rainfall days in September: 8.6 days
The month with the highest number of rainy days is June (13.9 days).
The month with the least rainy days is February (2.6 days).
Average snowfall in September
Westby, MT
- Average snowfall in September: 0"
The month with the highest snowfall is November (3.74").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Westby, MT
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (13.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Westby, MT
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 18min).
- Average sunshine in September: 9h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 3h and 54min).
Average sunshine days in September
Westby, MT
- Average sunshine days in September: 19.6 days
The month with the most sunshine days is August (20.1 days).
The months with the least sunshine days are February and June (13.8 days).
Average UV index in September
Westby, MT
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is February (UV index 1).
Average cloud cover in September
Westby, MT
- Average cloud cover in September: 26
The month with the most cloud cover is February (Cloud cover 60).
The months with the least cloud cover are July and August (Cloud cover 19).
Average visibility in September
Westby, MT
- 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).
Westby, Montana, USA
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