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
September brings a minor decrease, with the average high-temperature reducing from a warm 83.3°F (28.5°C) in August to an agreeable 72.5°F (22.5°C). The September nights bear witness to a significant drop from the daytime highs, settling at an average temperature of 48.2°F (9°C).Humidity
In September, the average relative humidity is 52%.Rainfall
In September, the rain falls for 7.9 days. Throughout September, 0.63" (16mm) of precipitation is accumulated. In Millwood, during the entire year, the rain falls for 125.4 days and collects up to 17.28" (439mm) of precipitation.Snowfall
Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.35" (9mm) of snow. Throughout the year, there are 56.4 snowfall days, and 37.4" (950mm) of snow is accumulated.Daylight
In September, the average length of the day is 12h and 33min.On the first day of September, sunrise is at 6:08 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:29 pm PDT.
Sunshine
The average sunshine in September is 10.1h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the average person.Note: An average UV index of 4 in September transforms into this advice:
Take precautions - Protection against sun damage is advised. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Take note! UV radiation from the Sun can double in intensity due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How many days does it rain in September?
When does it start snowing?
How many hours of daylight does Millwood have in September?
What time are sunrise and sunset in September in Millwood?
How many hours of sunshine does Millwood have in September?
What is the UV index intensity in September?
Average temperature in September
Millwood, WA
- Average high temperature in September: 72.5°F
The warmest month (with the highest average high temperature) is August (83.3°F).
The month with the lowest average high temperature is December (32°F).
- Average low temperature in September: 48.2°F
The month with the highest average low temperature is August (55.9°F).
The coldest month (with the lowest average low temperature) is December (21.9°F).
Average pressure in September
Millwood, WA
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in September
Millwood, WA
- Average wind speed in September: 4.9mph
The windiest month (with the highest average wind speed) is April (6.1mph).
The calmest month (with the lowest average wind speed) is December (4.7mph).
Average humidity in September
Millwood, WA
- Average humidity in September: 52%
The month with the highest relative humidity is January (91%).
The month with the lowest relative humidity is August (43%).
Average rainfall in September
Millwood, WA
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is January (2.28").
The driest months (with the least rainfall) are July and August (0.35").
Average rainfall days in September
Millwood, WA
- Average rainfall days in September: 7.9 days
The month with the highest number of rainy days is March (16 days).
The month with the least rainy days is July (5.1 days).
Average snowfall in September
Millwood, WA
- Average snowfall in September: 0.35"
The month with the highest snowfall is January (10.51").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Millwood, WA
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (13.9 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Millwood, 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: 10h and 1min
The month with the most sunshine is August (Average sunshine: 12h and 0min).
The months with the least sunshine are January and December (Average sunshine: 3h and 48min).
Average sunshine days in September
Millwood, WA
- Average sunshine days in September: 20.8 days
The month with the most sunshine days is July (24.3 days).
The month with the least sunshine days is March (10.3 days).
Average UV index in September
Millwood, WA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Millwood, WA
- Average cloud cover in September: 21
The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are July and August (Cloud cover 13).
Average visibility in September
Millwood, WA
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February and December (4mi).
Millwood, Washington, USA
Weather forecast for your location
2. Allow the app to use your location