September weather forecastLa Salle, MT
September
Weather in September
September, the first month of the autumn in La Salle, is still a comfortable month, with an average temperature fluctuating between 39.9°F (4.4°C) and 65.7°F (18.7°C).Temperature
The shift to September brings a decrease in the average high-temperature, falling from a warm 77.4°F (25.2°C) in August to a comfortable 65.7°F (18.7°C). La Salle endures a clear shift from daytime heat to a mean low-temperature of 39.9°F (4.4°C) during September nights.Humidity
In La Salle, Montana, the average relative humidity in September is 63%.Rainfall
In September, the rain falls for 8.6 days. Throughout September, 0.91" (23mm) of precipitation is accumulated. In La Salle, during the entire year, the rain falls for 142.8 days and collects up to 17.36" (441mm) of precipitation.Snowfall
Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.04" (1mm) of snow. Throughout the year, there are 104.7 snowfall days, and 51.34" (1304mm) of snow is accumulated.Daylight
In September, the average length of the day is 12h and 34min.On the first day of the month, sunrise is at 6:55 am and sunset at 8:17 pm. On the last day of September, sunrise is at 7:36 am and sunset at 7:17 pm MDT.
Sunshine
The average sunshine in September is 9.4h.UV index
The average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the average person.Note: A maximum UV index of 3 in September translates into the following recommendations:
Act with care - The need to guard against sun damage is communicated. The solar radiation around mid-day is intense; avoid the Sun and stay safe. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim. Guard yourself! Snow reflection can almost double the UV radiation from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
La Salle, MT
- Average high temperature in September: 65.7°F
The warmest month (with the highest average high temperature) is July (77.5°F).
The month with the lowest average high temperature is December (25.9°F).
- Average low temperature in September: 39.9°F
The month with the highest average low temperature is August (46.4°F).
The coldest month (with the lowest average low temperature) is February (14.4°F).
Average pressure in September
La Salle, MT
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
La Salle, MT
- Average wind speed in September: 3.8mph
The windiest month (with the highest average wind speed) is April (4.7mph).
The calmest month (with the lowest average wind speed) is August (3.7mph).
Average humidity in September
La Salle, MT
- Average humidity in September: 63%
The month with the highest relative humidity is January (93%).
The month with the lowest relative humidity is August (55%).
Average rainfall in September
La Salle, MT
- Average rainfall in September: 0.91"
The wettest month (with the highest rainfall) is June (2.05").
The driest month (with the least rainfall) is August (0.55").
Average rainfall days in September
La Salle, MT
- Average rainfall days in September: 8.6 days
The month with the highest number of rainy days is April (17.9 days).
The month with the least rainy days is August (6.6 days).
Average snowfall in September
La Salle, MT
- Average snowfall in September: 0.04"
The month with the highest snowfall is January (11.3").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
La Salle, MT
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (21.5 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
La Salle, MT
- Average daylight in September: 12h and 36min
The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 24min).
- Average sunshine in September: 9h and 24min
The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
La Salle, MT
- Average sunshine days in September: 19.6 days
The month with the most sunshine days is August (21.8 days).
The month with the least sunshine days is February (6.8 days).
Average UV index in September
La Salle, MT
- Average UV index in September: 3
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in September
La Salle, MT
- Average cloud cover in September: 23
The month with the most cloud cover is January (Cloud cover 63).
The months with the least cloud cover are July and August (Cloud cover 15).
Average visibility in September
La Salle, MT
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August, September and October (6mi).
The month with the lowest visibility is January (3mi).
