Just like with rainfall, we examine the accumulation of snowfall over a sliding 31-day period centred on each day of the year. Monthly snowfall varies by season in Seattle.
The snowy season lasts 1.3 months, from December 12 to January 20, and averages at least 1.0 inches of snowfall every 31 days. January is the snowiest month in Seattle, with an average snowfall of 1.2 inches.
Read Also: Does it snow in Seattle in November
The snow-free season lasts 11 months, from January 20 to December 12. Around July 1, the least amount of snow occurs, with an average accumulation of 0.0 inches.
Seattle Average Snowfall Per Month in: |
|
Month |
Average Inches of snow |
| January | 0.1 |
| February | 0.7 |
| March | 0.08 |
| November | 0.04 |
What months does it snow in Seattle?
Methodology
During the analysis period, between 8:00 AM and 9:00 PM, separate scores for felt temperature, cloud cover, and total precipitation are calculated each hour (1980 to 2016).
These scores are then pooled to form a single hourly composite score that is divided into days, averaged, and smoothed during the analysis period.
Our cloud cover rating system assigns a score of ten to a perfectly clear sky, nine to partially clear skies, and one to completely clouded skies.
Our rainfall rating is ten if there is no precipitation, nine if there is trace precipitation, and zero if there is at least 0.04 inches of precipitation.
Read Also: Does it snow in Seattle in January?-The Snowiest Month
Our tourism temperature score is 0 when temperatures are considered to be below 50°F, 9 when temperatures are considered to be above 65°F, 10 when temperatures are considered to be above 75°F, 9 when temperatures are considered to be above 80°F, and 1 when temperatures are considered to be over 90°F.
Our beach/pool temperature score is 0 when the temperature is below 65°F, 9 when the temperature is perceived to be 75°F, 10 when the temperature is perceived to be 82°F, 9 when the temperature is perceived to be 90°F, and 1 when the temperature is perceived to be 100°F or above.
Humidity
The dew point is used to evaluate the level of humidity that is comfortable for humans since it indicates whether perspiration evaporates from the skin and thereby cools the body.
Lower dew points imply greater dryness, whilst higher dew points imply increased humidity. In contrast to temperature, which frequently fluctuates dramatically between night and day, the dew point moves more slowly, which means that while temperatures may drop at night, a muggy day is usually followed by a muggy night.
In Seattle, the perceived humidity level, as measured by the proportion of time when the humidity comfort level is muggy, oppressive, or uncomfortable, does not change greatly throughout the year, maintaining a nearly constant 0%.
Wind
This section describes the hourly average wind vector (direction and speed) across a large area at a ten-meter altitude. Wind direction and speed are strongly dependent on local geography and other factors, and they fluctuate more rapidly than hourly averages.
The average hourly wind speed in Seattle varies slightly throughout the year.
The windiest month of the year is October 15 to April 24, lasting 6.3 months and averaging wind speeds of more than 4.1 miles per hour. December is the windiest month in Seattle, with an average hourly wind speed of 5.1 miles per hour.
From April 24 to October 15, the calmer season lasts 5.7 months. July is Seattle’s calmest month, with an average hourly wind speed of 2.9 miles per hour. In Seattle, the major hourly wind direction varies throughout the year.
Between July 3 and September 20, the wind comes mostly from the north for 2.6 months, peaking at 46% on July 30. Between September 20 and July 3, the wind blows mostly from the south for 9.5 months, peaking at 57% on January 1.
The temperature of the water.
Seattle is situated on the shores of a significant body of water (e.g., the ocean, sea, or large lake). This section discusses the average surface temperature of water across a large area.
The average water temperature varies slightly throughout the year.
The warmer water season lasts 3.1 months, from June 24 to September 28, and averages above 54°F. August is the warmest month in Seattle, with an average temperature of 56°F.
From December 10 to April 11, the cooler water season lasts for 4.0 months, with an average temperature of less than 48°F. February is the coldest month in Seattle, with an average temperature of 46°F.