September weather forecastEureka, MT
September
Weather in September
September ushers in Autumn with a significant decrease in the temperature scaling down to 65.8°F (18.8°C) and interrupts the city's dry spell with a surge in rainfall. This month encompasses cooler temperatures leading to pleasant weather, suitable for various outdoor activities. Even though there is an increase in rainfall, the city does not compromise on its sunny days. Notably, September marks the end of consistent sunshine exceeding 10 hours per day. All these factors combined make it an optimal month for fall foliage viewing and hiking trips.Temperature
The start of September involves a temperature drop, moving from a warm 77.2°F (25.1°C) in August to an enjoyable 65.8°F (18.8°C). A steady average of 38.7°F (3.7°C) throughout September in Eureka underscores a considerable divergence from the daytime high.Humidity
In Eureka, Montana, the average relative humidity in September is 64%.Rainfall
In Eureka, in September, it is raining for 8.8 days, with typically 0.79" (20mm) of accumulated precipitation. In Eureka, during the entire year, the rain falls for 136.3 days and collects up to 15.35" (390mm) 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 0.4 snowfall days, it receives 0.28" (7mm) of snow. Throughout the year, in Eureka, there are 110.7 snowfall days, and 46.81" (1189mm) of snow is accumulated.Daylight
The average length of the day in September in Eureka is 12h and 34min.On the first day of the month, sunrise is at 6:58 am and sunset at 8:21 pm. On the last day of September, in Eureka, sunrise is at 7:39 am and sunset at 7:20 pm MDT.
Sunshine
In Eureka, the average sunshine in September is 9.1h.UV index
In September, the average daily maximum UV index in Eureka is 3. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for average individuals.Note: A daily high UV index of 3 in September leads to these guidelines:
Be vigilant - A duty to shield skin and eyes from injury exists. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Take precaution! The reflection from snow can almost double the UV radiation of the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Eureka, MT
- Average high temperature in September: 65.8°F
The warmest month (with the highest average high temperature) is July (77.4°F).
The month with the lowest average high temperature is December (25.5°F).
- Average low temperature in September: 38.7°F
The month with the highest average low temperature is August (45.1°F).
The coldest month (with the lowest average low temperature) is December (13.1°F).
Average pressure in September
Eureka, MT
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Eureka, MT
- Average wind speed in September: 3.8mph
The windiest month (with the highest average wind speed) is June (4.4mph).
The calmest month (with the lowest average wind speed) is December (3.4mph).
Average humidity in September
Eureka, MT
- Average humidity in September: 64%
The month with the highest relative humidity is January (95%).
The month with the lowest relative humidity is August (55%).
Average rainfall in September
Eureka, MT
- Average rainfall in September: 0.79"
The wettest month (with the highest rainfall) is March (1.85").
The driest month (with the least rainfall) is August (0.39").
Average rainfall days in September
Eureka, MT
- Average rainfall days in September: 8.8 days
The month with the highest number of rainy days is April (17 days).
The month with the least rainy days is August (6.1 days).
Average snowfall in September
Eureka, MT
- Average snowfall in September: 0.28"
The month with the highest snowfall is February (10").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Eureka, MT
- Average snowfall days in September: 0.4 days
The month with the highest number of snowfall days is December (22.1 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Eureka, 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 18min).
- Average sunshine in September: 9h and 6min
The month with the most sunshine is August (Average sunshine: 11h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 6min).
Average sunshine days in September
Eureka, MT
- Average sunshine days in September: 18.4 days
The month with the most sunshine days is August (21.6 days).
The month with the least sunshine days is March (6.3 days).
Average UV index in September
Eureka, 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
Eureka, MT
- Average cloud cover in September: 26
The month with the most cloud cover is January (Cloud cover 70).
The month with the least cloud cover is August (Cloud cover 15).
Average visibility in September
Eureka, MT
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August and September (6mi).
The month with the lowest visibility is January (2mi).
