September weather forecastBothell, WA
September
Weather in September
September in Bothell characterizes the onset of autumn, with summer's warmth gradually fading into the cooler embrace of fall. The landscape curiously blends the green of lingering summer with auburn hints of impending autumn. This month records a significant drop in the maximum temperature to 68.7°F (20.4°C). As the refreshing autumn breezes replace the warmth of August, September paves the way for the full autumnal splendor of October.Temperature
September's arrival subtly correlates with a reduction in the average high-temperature, down from a warm 74.8°F (23.8°C) in August to a pleasant 68.7°F (20.4°C). Throughout September, Bothell's nights cool down to an average of 50°F (10°C).Humidity
The average relative humidity in September is 76%.Rainfall
In Bothell, in September, it is raining for 12.5 days, with typically 1.46" (37mm) of accumulated precipitation. In Bothell, during the entire year, the rain falls for 166.9 days and collects up to 21.93" (557mm) of precipitation.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 6:28 am and sunset at 7:48 pm. On the last day of September, sunrise is at 7:07 am and sunset at 6:49 pm PDT.
Sunshine
In September, the average sunshine is 9.4h.UV index
The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: A daily maximum UV index of 3 in September translates into the following instructions:
Exercise caution. Those with pale skin may experience burns in less than half an hour. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Bothell, WA
- Average high temperature in September: 68.7°F
The warmest month (with the highest average high temperature) is August (74.8°F).
The month with the lowest average high temperature is December (42.6°F).
- Average low temperature in September: 50°F
The month with the highest average low temperature is August (53.1°F).
The coldest months (with the lowest average low temperature) are February and December (35.1°F).
Average pressure in September
Bothell, WA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).
Average wind speed in September
Bothell, WA
- Average wind speed in September: 3.8mph
The windiest months (with the highest average wind speed) are January and March (5.3mph).
The calmest month (with the lowest average wind speed) is August (3.4mph).
Average humidity in September
Bothell, WA
- Average humidity in September: 76%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is July (71%).
Average rainfall in September
Bothell, WA
- Average rainfall in September: 1.46"
The wettest month (with the highest rainfall) is January (2.87").
The driest month (with the least rainfall) is July (0.43").
Average rainfall days in September
Bothell, WA
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is November (17.9 days).
The month with the least rainy days is August (6.9 days).
Average snowfall in September
Bothell, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.42").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Bothell, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (2.5 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
Bothell, WA
- Average daylight in September: 12h and 30min
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: 9h and 24min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The months with the least sunshine are January and December (Average sunshine: 4h and 24min).
Average sunshine days in September
Bothell, WA
- Average sunshine days in September: 14.8 days
The month with the most sunshine days is August (21.9 days).
The month with the least sunshine days is April (10.5 days).
Average UV index in September
Bothell, WA
- Average UV index in September: 3
The months with the highest UV index are June and 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
Bothell, WA
- Average cloud cover in September: 32
The months with the most cloud cover are January and December (Cloud cover 55).
The month with the least cloud cover is August (Cloud cover 24).
Average visibility in September
Bothell, 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, March, November and December (5mi).
