September weather forecastEast Helena, MT
September
Weather in September
September in East Helena, Montana sees the beginning of fall, despite a late summer feel with the temperature still reaching up to 68.2°F (20.1°C). The vibrancy of summer slowly transforms into the calmness of autumn. A slight chill starts to touch the morning and evening air. Nature takes a dramatic turn from lush green to shades of gold and brown. East Helena in September is a splendid sight, an ode to the magic of autumn's arrival.Temperature
The shift from August to September involves a decrease in the average high-temperature, dropping from a moderately hot 78.1°F (25.6°C) to an agreeable 68.2°F (20.1°C). September nights in East Helena show a substantial disparity from the daytime peak with an average low-temperature of 43.9°F (6.6°C).Humidity
In September, the average relative humidity is 51%.Rainfall
In East Helena, during September, the rain falls for 8.1 days and regularly aggregates up to 0.94" (24mm) of precipitation. In East Helena, during the entire year, the rain falls for 123.7 days and collects up to 12.4" (315mm) of precipitation.Snowfall
Months with snowfall are January through May, September through December. September is the first month it typically snows in East Helena. Throughout September, in the average 0.7 snowfall days, it receives 1.77" (45mm) of snow. In East Helena, Montana, during the entire year, snow falls for 80.4 days and aggregates up to 34.88" (886mm) of snow.Daylight
In East Helena, the average length of the day in September is 12h and 32min.On the first day of September in East Helena, sunrise is at 6:48 am and sunset at 8:06 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 7:08 pm MDT.
Sunshine
The average sunshine in September is 9.7h.UV index
The average daily maximum UV index in September is 3. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: In September, a regular UV index of 3 translates into these guidelines:
Prioritize safety - Suggestions to prevent sun damage are offered. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. During bright days, sunglasses that offer UVA and UVB defense are recommended. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
East Helena, MT
- Average high temperature in September: 68.2°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is December (27.7°F).
- Average low temperature in September: 43.9°F
The month with the highest average low temperature is July (50.4°F).
The coldest month (with the lowest average low temperature) is December (14.2°F).
Average pressure in September
East Helena, MT
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
East Helena, MT
- Average wind speed in September: 5.9mph
The windiest month (with the highest average wind speed) is November (7.1mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity in September
East Helena, MT
- Average humidity in September: 51%
The month with the highest relative humidity is January (85%).
The months with the lowest relative humidity are July and August (46%).
Average rainfall in September
East Helena, MT
- Average rainfall in September: 0.94"
The wettest month (with the highest rainfall) is June (2.01").
The driest months (with the least rainfall) are January and December (0.63").
Average rainfall days in September
East Helena, MT
- Average rainfall days in September: 8.1 days
The month with the highest number of rainy days is May (15.8 days).
The month with the least rainy days is November (7 days).
Average snowfall in September
East Helena, MT
- Average snowfall in September: 1.77"
The month with the highest snowfall is February (6.18").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
East Helena, MT
- Average snowfall days in September: 0.7 days
The month with the highest number of snowfall days is February (16.2 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
East Helena, MT
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in September: 9h and 42min
The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is January (Average sunshine: 5h and 36min).
Average sunshine days in September
East Helena, MT
- Average sunshine days in September: 19.3 days
The month with the most sunshine days is July (20.5 days).
The month with the least sunshine days is April (9.8 days).
Average UV index in September
East Helena, MT
- Average UV index in September: 3
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
East Helena, MT
- Average cloud cover in September: 22
The month with the most cloud cover is February (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 15).
Average visibility in September
East Helena, MT
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February and December (5mi).
