NORTH SOUND, DEC. 19: The winter solstice is Sunday, marking the start of astronomical winter. On the solstice, sunrise will be at 7:55 a.m. and sunset at 4:18 p.m. in Everett.
That adds up to just 8 hours and 23 minutes of daylight—the shortest day of the year.
The winter solstice occurs when the sun is centered over the Tropic of Capricorn in the Southern Hemisphere at 23.5 degrees south, a result of the tilt of the Earth as it orbits the sun throughout the year.
The solstice also produces the year’s longest shadows since the peak sun angle above the horizon is at its lowest point, only about 19.7 degrees above the horizon. The solstice also marks the longest night of the year.
In contrast to the Southern Hemisphere, our solstice is their longest time period of daylight, just like the summer solstice here in mid-June. Also of interest, above the Arctic Circle, there is no daylight at all on the winter solstice, as well as several days before and after the solstice.
From a weather perspective, the seasons solstices since it takes time for the sun to warm the Earth’s surface, ground and water. As a result, January is historically the coldest month in the North Sound, while July is the warmest—even as daylight trends move in the opposite direction.
World History
The winter solstice has quite a history. Early humans tracked the days by observing the sun as it cast shadows at different times of the year. Historians believe Stonehenge in England was built to keep track of the sun’s annual progress across the sky.
Cultures across Scandinavia, parts of Eastern Asia, and countries such as India, Iran, Ireland and Japan have long celebrated the solstice. In the Southern Hemisphere, many celebrate the summer solstice.
Winter Weather Outlook
This period of warm, wet weather with periods of heavy rainfall, high snow levels, flooding, landslides and strong winds will all come to an end by this weekend. After the first day of winter, the region’s weather will feel more winter-like.
The weather outlook heading into the new year offers a classic La Niña pattern, bringing cooler temperatures and above-average precipitation. This outlook means rainfall in the lowlands and snow in the mountains.
Starting Friday, Dec. 19, mountain snow levels will drop below the passes, allowing snow to pile up. Moving into early next week, at least several feet of new snow is forecast to fall. It is quite possible that by Christmas Day, several ski areas will have enough snow to open up.
Snow on Christmas?
Many would like to see some snow in their backyards for Christmas. Historically, there is only about a 7% chance of snow on the ground on Christmas Day in the North Sound.
If current longer-range forecast guidance is on track, cooler air from the interior of Western Canada is forecast to slide south into the North Sound and Western Washington. This weather pattern would cool the existing air mass enough to bring snow levels lower, including the foothills. Communities near the Canadian border, such as Bellingham, would also have an even better chance.
Longer Days Coming
After the winter solstice, daylight will begin to grow longer, at first slowly as a matter of seconds, and then by the spring equinox in March, peaking at around three and a half minutes per day. The increase of daylight will then gradually slow, ending on the Summer Solstice in mid-June with just over 16 hours of daylight.
As I often joked just after the winter solstice when working at the National Weather Service, summer is coming!
