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
In September, the meteorological conditions change slightly, with the average high-temperature moving from a pleasant 72.7°F (22.6°C) in August to a refreshing 67.1°F (19.5°C). During September nights, Mill Creek witnesses a consistent average temperature of 51.4°F (10.8°C).Humidity
The average relative humidity in September is 77%.Rainfall
In September, in Mill Creek, Washington, the rain falls for 11.3 days. Throughout September, 1.5" (38mm) of precipitation is accumulated. In Mill Creek, during the entire year, the rain falls for 173.1 days and collects up to 26.02" (661mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
The average length of the day in September in Mill Creek is 12h and 33min.On the first day of September in Mill Creek, sunrise is at 6:28 am and sunset at 7:48 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 6:49 pm PDT.
Sunshine
In September, the average sunshine in Mill Creek is 9.4h.UV index
In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Undertake protective steps - Preventing sun damage is advised. Minimize direct exposure to the Sun during midday when its radiation is at its peak. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses.
Frequently asked questions
What is the temperature in September in Mill Creek?
What is the average humidity in September in Mill Creek?
How much does it rain in Mill Creek in September?
When it does not snow in Mill Creek?
What is the average length of the day in September in Mill Creek?
When is the sunrise / sunset in September in Mill Creek?
How long on average sun shines in September in Mill Creek?
What is the UV index reading in September in Mill Creek?
Average temperature in September
Mill Creek, WA
- Average high temperature in September: 67.1°F
The warmest month (with the highest average high temperature) is August (72.7°F).
The month with the lowest average high temperature is December (42.6°F).
- Average low temperature in September: 51.4°F
The month with the highest average low temperature is August (54°F).
The coldest month (with the lowest average low temperature) is December (35.4°F).
Average pressure in September
Mill Creek, WA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).
Average wind speed in September
Mill Creek, WA
- Average wind speed in September: 4.2mph
The windiest month (with the highest average wind speed) is November (6.2mph).
The calmest month (with the lowest average wind speed) is August (3.6mph).
Average humidity in September
Mill Creek, WA
- Average humidity in September: 77%
The months with the highest relative humidity are February and December (84%).
The month with the lowest relative humidity is July (72%).
Average rainfall in September
Mill Creek, WA
- Average rainfall in September: 1.5"
The wettest month (with the highest rainfall) is December (3.54").
The driest month (with the least rainfall) is July (0.43").
Average rainfall days in September
Mill Creek, WA
- Average rainfall days in September: 11.3 days
The month with the highest number of rainy days is March (19.8 days).
The month with the least rainy days is August (6.3 days).
Average snowfall in September
Mill Creek, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (4.61").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Mill Creek, 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
Mill Creek, 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: 9h and 2min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days in September
Mill Creek, WA
- Average sunshine days in September: 16.5 days
The month with the most sunshine days is August (22.6 days).
The month with the least sunshine days is November (9.1 days).
Average UV index in September
Mill Creek, WA
- Average UV index in September: 4
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 2).
Average cloud cover in September
Mill Creek, WA
- Average cloud cover in September: 32
The month with the most cloud cover is December (Cloud cover 54).
The month with the least cloud cover is August (Cloud cover 25).
Average visibility in September
Mill Creek, WA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
Mill Creek, Washington, USA
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