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
Onset of September comes with a temperature decline, the average high falling from a warm 78.8°F (26°C) in August to a refreshing 67.3°F (19.6°C). The significant decline in Plains's temperature, from day to night, averages of 39.7°F (4.3°C) in September.Humidity
The average relative humidity in September is 63%.Rainfall
In Plains, during September, the rain falls for 7.8 days and regularly aggregates up to 0.59" (15mm) of precipitation. In Plains, during the entire year, the rain falls for 152.1 days and collects up to 22.09" (561mm) of precipitation.Snowfall
January through May, September through December are months with snowfall in Plains. September is the first month it typically snows. Throughout September, in the average 0.3 snowfall days, it receives 0.31" (8mm) of snow. Throughout the year, in Plains, there are 90.2 snowfall days, and 58.15" (1477mm) of snow is accumulated.Daylight
In September, the average length of the day in Plains is 12h and 32min.On the first day of the month, sunrise is at 6:59 am and sunset at 8:19 pm. On the last day of September, in Plains, sunrise is at 7:38 am and sunset at 7:20 pm MDT.
Sunshine
In September, the average sunshine is 9h.UV index
The average daily maximum UV index in September in Plains is 3. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: A daily high UV index of 3 in September leads to these guidelines:
Take precautions - Protection against skin and eye damage is obliged. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures in Plains?
What is the average humidity in September in Plains?
How many days does it rain in September in Plains?
When does it start to snow in Plains?
What is the average length of the day in September in Plains?
When is the sunrise / sunset in September in Plains?
How long on average sun shines in September in Plains?
What is the UV index intensity in September in Plains?
Average temperature in September
Plains, MT
- Average high temperature in September: 67.3°F
The warmest months (with the highest average high temperature) are July and August (78.8°F).
The month with the lowest average high temperature is December (28.9°F).
- Average low temperature in September: 39.7°F
The month with the highest average low temperature is August (45.7°F).
The coldest month (with the lowest average low temperature) is December (16.2°F).
Average pressure in September
Plains, MT
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Plains, MT
- Average wind speed in September: 4.2mph
The windiest month (with the highest average wind speed) is April (4.9mph).
The calmest month (with the lowest average wind speed) is December (4mph).
Average humidity in September
Plains, MT
- Average humidity in September: 63%
The month with the highest relative humidity is January (93%).
The months with the lowest relative humidity are July and August (53%).
Average rainfall in September
Plains, MT
- Average rainfall in September: 0.59"
The wettest month (with the highest rainfall) is January (3.11").
The driest month (with the least rainfall) is August (0.39").
Average rainfall days in September
Plains, MT
- Average rainfall days in September: 7.8 days
The month with the highest number of rainy days is March (19.9 days).
The month with the least rainy days is August (5.9 days).
Average snowfall in September
Plains, MT
- Average snowfall in September: 0.31"
The month with the highest snowfall is February (15.12").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Plains, MT
- Average snowfall days in September: 0.3 days
The month with the highest number of snowfall days is December (20.4 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Plains, MT
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 9h and 0min
The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in September
Plains, MT
- Average sunshine days in September: 20.3 days
The months with the most sunshine days are July and August (23.3 days).
The month with the least sunshine days is March (5.8 days).
Average UV index in September
Plains, 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
Plains, MT
- Average cloud cover in September: 25
The month with the most cloud cover is February (Cloud cover 66).
The months with the least cloud cover are July and August (Cloud cover 15).
Average visibility in September
Plains, MT
- Average visibility in September: 6mi
The months with the highest visibility are June, July, August and September (6mi).
The months with the lowest visibility are January, February and December (3mi).
Plains, Montana, USA
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