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
With the onset of September, Roy's average high-temperature adjusts, receding from August's warm 78.1°F (25.6°C) to an enjoyable 67.5°F (19.7°C). In Roy, the average low-temperature during the month of September is a chilly 47.1°F (8.4°C).Humidity
In Roy, the average relative humidity in September is 52%.Rainfall
In Roy, during September, the rain falls for 8.7 days and regularly aggregates up to 1.02" (26mm) of precipitation. In Roy, Montana, during the entire year, the rain falls for 126.2 days and collects up to 17.83" (453mm) of precipitation.Snowfall
January through June, September through December are months with snowfall in Roy. September is the first month it typically snows. Throughout September, in the average 1 snowfall days, it receives 1.3" (33mm) of snow. In Roy, Montana, during the entire year, snow falls for 83.4 days and aggregates up to 45.51" (1156mm) of snow.Daylight
In September, the average length of the day is 12h and 32min.On the first day of the month, sunrise is at 6:35 am and sunset at 7:55 pm. On the last day of September, sunrise is at 7:14 am and sunset at 6:56 pm MDT.
Sunshine
The average sunshine in September is 10h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Prioritize safety - Suggestions to prevent sun damage are offered. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection. Pay attention! The reflection of snow can enhance the Sun's UV radiation almost double.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature in Roy?
What is the average humidity in September in Roy?
How much does it rain in Roy in September?
When does it start to snow in Roy?
How many hours of daylight does Roy have in September?
What time are sunrise and sunset in September in Roy?
How long on average sun shines in September in Roy?
What is the UV index intensity in September in Roy?
Average temperature in September
Roy, MT
- Average high temperature in September: 67.5°F
The warmest month (with the highest average high temperature) is July (78.8°F).
The months with the lowest average high temperature are February and December (29.1°F).
- Average low temperature in September: 47.1°F
The month with the highest average low temperature is August (54.5°F).
The coldest month (with the lowest average low temperature) is February (15.3°F).
Average pressure in September
Roy, MT
- Average pressure in September: 29.94"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in September
Roy, MT
- Average wind speed in September: 8.5mph
The windiest months (with the highest average wind speed) are January, April and October (9.9mph).
The calmest month (with the lowest average wind speed) is August (7.4mph).
Average humidity in September
Roy, MT
- Average humidity in September: 52%
The month with the highest relative humidity is February (79%).
The month with the lowest relative humidity is August (47%).
Average rainfall in September
Roy, MT
- Average rainfall in September: 1.02"
The wettest month (with the highest rainfall) is May (3.39").
The driest month (with the least rainfall) is December (0.71").
Average rainfall days in September
Roy, MT
- Average rainfall days in September: 8.7 days
The month with the highest number of rainy days is May (19.3 days).
The month with the least rainy days is January (5.4 days).
Average snowfall in September
Roy, MT
- Average snowfall in September: 1.3"
The month with the highest snowfall is April (9.13").
The months with the least snowfall are July and August (0").
Average snowfall days in September
Roy, MT
- Average snowfall days in September: 1 days
The month with the highest number of snowfall days is February (15.2 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Roy, 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: 10h and 0min
The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 30min).
Average sunshine days in September
Roy, MT
- Average sunshine days in September: 19.3 days
The month with the most sunshine days is September (19.3 days).
The month with the least sunshine days is April (8.3 days).
Average UV index in September
Roy, MT
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).
Average cloud cover in September
Roy, MT
- Average cloud cover in September: 23
The month with the most cloud cover is February (Cloud cover 45).
The month with the least cloud cover is July (Cloud cover 16).
Average visibility in September
Roy, MT
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Roy, Montana, USA
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