September weather forecastLake McDonald, MT
September
Weather in September
The first month of the autumn, September, is also an enjoyable month in Lake McDonald, Montana, with an average temperature ranging between max 65.5°F (18.6°C) and min 39.2°F (4°C).Temperature
During Lake McDonald's transition into September, the average high-temperature lessens, moving from a warm 76.8°F (24.9°C) in August to a comfortable 65.5°F (18.6°C). September nights showcase a dramatic shift from daytime highs to an average temperature of 39.2°F (4°C).Humidity
The average relative humidity in September is 64%.Rainfall
In Lake McDonald, during September, the rain falls for 8.5 days and regularly aggregates up to 0.71" (18mm) of precipitation. Throughout the year, there are 126.4 rainfall days, and 11.22" (285mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.3 snowfall days, it receives 0.04" (1mm) of snow. In Lake McDonald, during the entire year, snow falls for 97 days and aggregates up to 33.86" (860mm) of snow.Daylight
In Lake McDonald, Montana, the average length of the day in September is 12h and 34min.On the first day of the month, sunrise is at 6:54 am and sunset at 8:16 pm. On the last day of September, sunrise is at 7:34 am and sunset at 7:15 pm MDT.
Sunshine
In Lake McDonald, the average sunshine in September is 9.4h.UV index
In Lake McDonald, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for the ordinary person.Note: The maximum UV index of 3 during September translates into these guidelines:
Take necessary precautions - Suggestions to elude sunburn are provided. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Lake McDonald, MT
- Average high temperature in September: 65.5°F
The warmest month (with the highest average high temperature) is July (77.9°F).
The month with the lowest average high temperature is December (25.7°F).
- Average low temperature in September: 39.2°F
The month with the highest average low temperature is August (45.5°F).
The coldest month (with the lowest average low temperature) is February (13.5°F).
Average pressure in September
Lake McDonald, 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
Lake McDonald, MT
- Average wind speed in September: 3.8mph
The windiest month (with the highest average wind speed) is April (4.6mph).
The calmest months (with the lowest average wind speed) are August and December (3.7mph).
Average humidity in September
Lake McDonald, MT
- Average humidity in September: 64%
The month with the highest relative humidity is January (93%).
The month with the lowest relative humidity is August (55%).
Average rainfall in September
Lake McDonald, MT
- Average rainfall in September: 0.71"
The wettest month (with the highest rainfall) is June (1.42").
The driest month (with the least rainfall) is August (0.43").
Average rainfall days in September
Lake McDonald, MT
- Average rainfall days in September: 8.5 days
The month with the highest number of rainy days is April (15.8 days).
The month with the least rainy days is August (6.3 days).
Average snowfall in September
Lake McDonald, MT
- Average snowfall in September: 0.04"
The month with the highest snowfall is January (7.72").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Lake McDonald, MT
- Average snowfall days in September: 0.3 days
The month with the highest number of snowfall days is December (19.1 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Lake McDonald, MT
- Average daylight in September: 12h and 36min
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 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 30min).
Average sunshine days in September
Lake McDonald, MT
- Average sunshine days in September: 19 days
The month with the most sunshine days is July (21.5 days).
The month with the least sunshine days is March (7.7 days).
Average UV index in September
Lake McDonald, MT
- Average UV index in September: 3
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in September
Lake McDonald, MT
- Average cloud cover in September: 24
The month with the most cloud cover is January (Cloud cover 65).
The months with the least cloud cover are July and August (Cloud cover 15).
Average visibility in September
Lake McDonald, 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).
