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
Snoqualmie Pass's September weather features a mild decline in high-temperatures, reducing from an agreeable 71.2°F (21.8°C) in August to a refreshing 62.1°F (16.7°C). In Snoqualmie Pass, the expected average low-temperature for September is a wintry 41.2°F (5.1°C).Humidity
In September, the average relative humidity is 75%.Rainfall
In Snoqualmie Pass, during September, the rain falls for 11.8 days and regularly aggregates up to 1.06" (27mm) of precipitation. Throughout the year, there are 127.9 rainfall days, and 28.58" (726mm) of precipitation is accumulated.Snowfall
January through June, September through December are months with snowfall in Snoqualmie Pass. September is the first month it typically snows. Throughout September, in the average 0.8 snowfall days, it receives 0.24" (6mm) of snow. Throughout the year, there are 135.3 snowfall days, and 134.33" (3412mm) of snow is accumulated.Daylight
The average length of the day in September is 12h and 32min.On the first day of the month, sunrise is at 6:25 am and sunset at 7:45 pm. On the last day of September, in Snoqualmie Pass, sunrise is at 7:04 am and sunset at 6:46 pm PDT.
Sunshine
The average sunshine in September is 8.7h.UV index
In September, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a low health risk from unsafe exposure to UV radiation for average individuals.Note: A typical high UV index of 2 in September suggests the following recommendations:
Extended exposure to the sun should always be avoided by children, infants, and those with sensitive skin. It's recommended to limit sun exposure when its radiation is at its peak during midday. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Beware! Reflection from snow can magnify the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
How many days does it rain in September in Snoqualmie Pass?
When does it start snowing?
What is the average length of the day in September in Snoqualmie Pass?
When is the sunrise / sunset in September?
How many hours of sunshine does Snoqualmie Pass have in September?
What is the UV index intensity in September?
Average temperature in September
Snoqualmie Pass, WA
- Average high temperature in September: 62.1°F
The warmest month (with the highest average high temperature) is August (71.2°F).
The month with the lowest average high temperature is December (30.2°F).
- Average low temperature in September: 41.2°F
The month with the highest average low temperature is August (45°F).
The coldest month (with the lowest average low temperature) is December (20.3°F).
Average pressure in September
Snoqualmie Pass, WA
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is August (29.97"Hg).
Average wind speed in September
Snoqualmie Pass, WA
- Average wind speed in September: 3.9mph
The windiest month (with the highest average wind speed) is January (5mph).
The calmest month (with the lowest average wind speed) is September (3.9mph).
Average humidity in September
Snoqualmie Pass, WA
- Average humidity in September: 75%
The months with the highest relative humidity are January and February (93%).
The month with the lowest relative humidity is July (69%).
Average rainfall in September
Snoqualmie Pass, WA
- Average rainfall in September: 1.06"
The wettest month (with the highest rainfall) is January (4.21").
The driest month (with the least rainfall) is July (0.51").
Average rainfall days in September
Snoqualmie Pass, WA
- Average rainfall days in September: 11.8 days
The month with the highest number of rainy days is May (15.7 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in September
Snoqualmie Pass, WA
- Average snowfall in September: 0.24"
The month with the highest snowfall is January (27.72").
The months with the least snowfall are July and August (0").
Average snowfall days in September
Snoqualmie Pass, WA
- Average snowfall days in September: 0.8 days
The month with the highest number of snowfall days is December (22.3 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Snoqualmie Pass, WA
- 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: 8h and 4min
The month with the most sunshine is August (Average sunshine: 10h and 54min).
The months with the least sunshine are January and February (Average sunshine: 3h and 0min).
Average sunshine days in September
Snoqualmie Pass, WA
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is August (20.2 days).
The month with the least sunshine days is February (6 days).
Average UV index in September
Snoqualmie Pass, WA
- Average UV index in September: 2
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in September
Snoqualmie Pass, WA
- Average cloud cover in September: 43
The month with the most cloud cover is February (Cloud cover 72).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Snoqualmie Pass, WA
- Average visibility in September: 4mi
The months with the highest visibility are June, July and August (5mi).
The months with the lowest visibility are January, February, March and December (3mi).
Snoqualmie Pass, Washington, USA
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