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 sea temperature 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
Friday Harbor records an average high-temperature of a still enjoyable 61.3°F (16.3°C) as September arrives, nearly mirroring the previous month's climate. Friday Harbor consistently logs a low temperature averaging a mild 55.6°F (13.1°C) during September, a modest drop from daytime temperatures.Humidity
January, August and September, with an average relative humidity of 79%, are the most humid months.Rainfall
In Friday Harbor, Washington, in September, during 11.6 rainfall days, 1.34" (34mm) of precipitation is typically accumulated. In Friday Harbor, during the entire year, the rain falls for 167.7 days and collects up to 23.46" (596mm) of precipitation.Snowfall
In Friday Harbor, Washington, snow does not fall in April through October.Ocean temperature
August and September, with an average ocean temperature of 52.3°F (11.3°C), are months with the warmest seawater.Note: Being in 52.3°F (11.3°C) waters at 55.4°F (13°C) is discomforting, but anything below 50°F (10°C) can jeopardize breathing and induce cold shock, factoring in physical endurance.
Daylight
In September, the average length of the day in Friday Harbor is 12h and 34min.On the first day of the month, sunrise is at 6:30 am and sunset at 7:53 pm. On the last day of September, sunrise is at 7:11 am and sunset at 6:52 pm PDT.
Sunshine
In Friday Harbor, the average sunshine in September is 9.4h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum daily UV index of 4 during September translates into the following directions:
Heed the precautions - It is counselled to guard against solar damage. Around midday, solar radiation is most harmful; hence, exposure should be limited. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What are the most humid months?
What is the average humidity in September?
How much does it rain in Friday Harbor in September?
When it does not snow?
What months are the ocean warmest?
How cold is the water in September?
How many hours of daylight does Friday Harbor have in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Friday Harbor, WA
- Average high temperature in September: 61.3°F
The warmest month (with the highest average high temperature) is July (64.9°F).
The months with the lowest average high temperature are January, February and December (45.3°F).
- Average low temperature in September: 55.6°F
The month with the highest average low temperature is August (57.7°F).
The coldest month (with the lowest average low temperature) is February (40.5°F).
Average pressure in September
Friday Harbor, WA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.07"Hg).
The month with the lowest atmospheric pressure is March (30"Hg).
Average wind speed in September
Friday Harbor, WA
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is November (10.7mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).
Average humidity in September
Friday Harbor, WA
- Average humidity in September: 79%
The months with the highest relative humidity are January, August and September (79%).
The month with the lowest relative humidity is April (76%).
Average rainfall in September
Friday Harbor, WA
- Average rainfall in September: 1.34"
The wettest month (with the highest rainfall) is November (3.43").
The driest month (with the least rainfall) is July (0.43").
Average rainfall days in September
Friday Harbor, WA
- Average rainfall days in September: 11.6 days
The month with the highest number of rainy days is March (20.2 days).
The month with the least rainy days is August (5.3 days).
Average snowfall in September
Friday Harbor, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.77").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Friday Harbor, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (2.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in September
Friday Harbor, WA
- Average sea temperature in September: 52.3°F
The best months for swimming (with the highest average sea temperature) are August and September (52.3°F).
The coldest month (with the lowest average sea temperature) is February (44.9°F).
Average daylight in September /
Average sunshine in September
Friday Harbor, WA
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 24min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is July (Average sunshine: 11h and 6min).
The month with the least sunshine is December (Average sunshine: 4h and 6min).
Average sunshine days in September
Friday Harbor, WA
- Average sunshine days in September: 17.4 days
The month with the most sunshine days is August (24.7 days).
The month with the least sunshine days is November (8.7 days).
Average UV index in September
Friday Harbor, 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
Friday Harbor, WA
- Average cloud cover in September: 32
The months with the most cloud cover are February and December (Cloud cover 56).
The months with the least cloud cover are July and August (Cloud cover 23).
Average visibility in September
Friday Harbor, WA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Friday Harbor, Washington, USA
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