Contents
- Weather in January
- Frequently asked questions
- Average temperature in January
- Average pressure in January
- Average wind speed in January
- Average humidity in January
- Average rainfall in January
- Average rainfall days in January
- Average snowfall in January
- Average snowfall days in January
- Average sea temperature in January
- Average daylight in January
- Average sunshine in January
- Average sunshine days in January
- Average UV index in January
- Average cloud cover in January
- Average visibility in January
January
Weather in January
Temperature
Seattle starts January with an average high-temperature of a still chilly 45°F (7.2°C), hinting at a minimal fluctuation from December. Night temperatures in January exhibit a subtle decrease, settling at an average of 36°F (2.2°C).Humidity
The most humid month is January, with an average relative humidity of 85%.Rainfall
In Seattle, in January, during 8.8 rainfall days, 0.71" (18mm) of precipitation is typically accumulated. In Seattle, during the entire year, the rain falls for 84.2 days and collects up to 5.2" (132mm) of precipitation.Snowfall
Months with snowfall are January through March and November. January is the first month it typically snows. Throughout January, in the average 1.3 snowfall days, it receives 0.12" (3mm) of snow. In Seattle, during the entire year, snow falls for 4.8 days and aggregates up to 0.94" (24mm) of snow.Ocean temperature
In January, the average ocean temperature is 45.5°F (7.5°C).Note: Swimming at temperatures less than 50°F (10°C) in 45.5°F (7.5°C) is feasible with the right swimsuit; if not, expect cold shock and breathlessness. A quick swim at 55.4°F (13°C) without adequate warmth can be discomforting.
Daylight
In Seattle, the average length of the day in January is 8h and 58min.On the first day of January, sunrise is at 7:57 am and sunset at 4:28 pm. On the last day of the month, sunrise is at 7:37 am and sunset at 5:08 pm PST.
Sunshine
In January, the average sunshine is 4.4h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a minimal health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: The maximum daily UV index of 2 in January converts into the following recommendations:
Most people face no serious problems with extended sun exposure, but those with fair skin, infants, and children always need protection. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Seattle in January?
What is the most humid month?
What is the average humidity in January?
How many days does it rain in January?
When does it start to snow?
What is the water temperature in January?
How many hours of daylight does Seattle have in January?
When are sunrise and sunset in January in Seattle?
How long on average sun shines in January?
What is the month with the lowest UV index in Seattle?
How high is the UV index in January in Seattle?
Average temperature in January
Seattle, WA
- Average high temperature in January: 45°F
The warmest month (with the highest average high temperature) is August (76.3°F).
The month with the lowest average high temperature is December (43.7°F).
- Average low temperature in January: 36°F
The month with the highest average low temperature is August (54°F).
The coldest month (with the lowest average low temperature) is December (35.1°F).
Average pressure in January
Seattle, WA
- Average pressure in January: 30.1"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).
Average wind speed in January
Seattle, WA
- Average wind speed in January: 5.2mph
The windiest month (with the highest average wind speed) is March (5.3mph).
The calmest months (with the lowest average wind speed) are July and August (3.5mph).
Average humidity in January
Seattle, WA
- Average humidity in January: 85%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is July (69%).
Average rainfall in January
Seattle, WA
- Average rainfall in January: 0.71"
The wettest month (with the highest rainfall) is December (0.87").
The driest months (with the least rainfall) are July and August (0.12").
Average rainfall days in January
Seattle, WA
- Average rainfall days in January: 8.8 days
The month with the highest number of rainy days is November (9.1 days).
The month with the least rainy days is August (2.8 days).
Average snowfall in January
Seattle, WA
- Average snowfall in January: 0.12"
The month with the highest snowfall is February (0.71").
The months with the least snowfall are April, May, June, July, August, September, October and December (0").
Average snowfall days in January
Seattle, WA
- Average snowfall days in January: 1.3 days
The month with the highest number of snowfall days is February (1.9 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in January
Seattle, WA
- Average sea temperature in January: 45.6°F
The best month for swimming (with the highest average sea temperature) is August (53.5°F).
The coldest month (with the lowest average sea temperature) is February (45.3°F).
Average daylight in January /
Average sunshine in January
Seattle, WA
- Average daylight in January: 9h and 0min
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 January: 4h and 2min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 18min).
Average sunshine days in January
Seattle, WA
- Average sunshine days in January: 18.8 days
The month with the most sunshine days is August (25.9 days).
The month with the least sunshine days is November (16.8 days).
Average UV index in January
Seattle, WA
- Average UV index in January: 2
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in January
Seattle, WA
- Average cloud cover in January: 55
The month with the most cloud cover is December (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 25).
Average visibility in January
Seattle, WA
- Average visibility in January: 5mi
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).