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
The start of September comes with a small reduction in the average high-temperature, subtly receding from a warm 73.4°F (23°C) in August to a refreshing 66.4°F (19.1°C). Startup throughout September, records an average low-temperature of 45°F (7.2°C).Humidity
The average relative humidity in September in Startup is 77%.Rainfall
In Startup, Washington, in September, during 12.8 rainfall days, 2.24" (57mm) of precipitation is typically accumulated. Throughout the year, in Startup, there are 200.6 rainfall days, and 51.65" (1312mm) of precipitation is accumulated.Snowfall
May through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 33min.On the first day of the month, sunrise is at 6:26 am and sunset at 7:47 pm. On the last day of September, sunrise is at 7:05 am and sunset at 6:47 pm PDT.
Sunshine
The average sunshine in September is 8.7h.UV index
In Startup, Washington, the average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: In September, the UV index of 3 transforms into the following advice:
Make use of precautions - Shielding skin and eyes from injury is a requirement. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in Startup in September?
What is the average humidity in September in Startup?
How much does it rain in Startup in September?
When it does not snow in Startup?
How many hours of daylight does Startup have in September?
What time are sunrise and sunset in September in Startup?
How many hours of sunshine does Startup have in September?
What is the UV index intensity in September in Startup?
Average temperature in September
Startup, WA
- Average high temperature in September: 66.4°F
The warmest month (with the highest average high temperature) is August (73.4°F).
The month with the lowest average high temperature is December (38.3°F).
- Average low temperature in September: 45°F
The month with the highest average low temperature is August (48°F).
The coldest month (with the lowest average low temperature) is December (28.6°F).
Average pressure in September
Startup, WA
- Average pressure in September: 30"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is August (29.99"Hg).
Average wind speed in September
Startup, WA
- Average wind speed in September: 3.3mph
The windiest month (with the highest average wind speed) is January (4.8mph).
The calmest month (with the lowest average wind speed) is August (3.2mph).
Average humidity in September
Startup, WA
- Average humidity in September: 77%
The months with the highest relative humidity are January, February and March (88%).
The month with the lowest relative humidity is July (72%).
Average rainfall in September
Startup, WA
- Average rainfall in September: 2.24"
The wettest month (with the highest rainfall) is January (7.8").
The driest month (with the least rainfall) is August (0.79").
Average rainfall days in September
Startup, WA
- Average rainfall days in September: 12.8 days
The month with the highest number of rainy days is March (22.3 days).
The month with the least rainy days is August (7.9 days).
Average snowfall in September
Startup, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.43").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Startup, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (5.2 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Startup, WA
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 0min).
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 24min).
The months with the least sunshine are January and December (Average sunshine: 3h and 42min).
Average sunshine days in September
Startup, WA
- Average sunshine days in September: 15 days
The month with the most sunshine days is August (19.9 days).
The month with the least sunshine days is March (7 days).
Average UV index in September
Startup, WA
- Average UV index in September: 3
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).
Average cloud cover in September
Startup, WA
- Average cloud cover in September: 41
The months with the most cloud cover are March and December (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Startup, WA
- Average visibility in September: 5mi
The months with the highest visibility are May, June, July, August, September and October (5mi).
The months with the lowest visibility are January, February, March, April, November and December (4mi).
Startup, Washington, USA
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