Seattle stunner: 59 degrees, then snow

It rained. It poured. The temperature soared.

And six hours later, there was snow across the board.

In stunning and dramatic fashion, Seattle skyrocketed to a spring-like 59 degrees yesterday amid torrential lunchtime rains, before plummeting into the mid-30s around dinnertime as snow began swirling over the city.

Oh, and did we mention that both the day’s high temperature and total rainfall set new records too?

That’s right, yesterday was both Seattle’s wettest and warmest Dec. 21 on record, with 1.64 inches of rain accompanying the unusually balmy temperatures that made it feel a far cry from the first day of winter—until the clock struck 3.

First hill pic.twitter.com/PJaJnQT8X9

— Kanika Gupta (@kanika027) December 22, 2020

At that hour, a powerful cold front—the kind more typical in Denver than Seattle—sliced through Puget Sound from north to south, sending temperatures tumbling from the 50s to the 30s as rain turned to snow. At Sea-Tac Airport, the mercury went from 54 degrees at 3:30 p.m. to 34 degrees just before 6 p.m. At Boeing Field, a 55-degree rain at 3 o’clock became a 40-degree rain at 4. By 8 p.m., it was 32 and snowing.

The staggering transition from warm rain to wet snow wasn’t just rare—it was also unprecedented, at least in the modern era. According to Dr. Joe Zagrodnik, yesterday was Seattle’s warmest day with observed snowfall in the entire climate record of Sea-Tac Airport (where records have been kept since 1945).

The bizarre stat-line from yesterday—high 59/low 34, with 0.5 inches of snow—eclipsed the previous warmest day with snow record from Nov. 15, 1975. On that day, the mercury peaked at 58 degrees before 0.2 inches of snow fell. Zagrodnik also notes that yesterday marked just the fifth time it’s snowed in Seattle on a day when temperatures reached into the 50s.

Yesterday was Seattle’s warmest day with snow since at least 1945 https://t.co/9sRE4QtciW

— Seattle Weather Blog (@KSeattleWeather) December 22, 2020

So, where do we go from here? Back to a much calmer, more typical weather pattern for this time of year. A mix of fog and sun will prevail over the region through Christmas Eve, with temperatures generally in the mid-40s during the day and near freezing overnight. Rain then returns on Christmas Day, with highs staying in the mid-40s.

For those of you pining for a White Christmas, it’s too bad that temperatures are unlikely to climb past 50 degrees. After all, in 2020, that appears to be the best way to lure snow to Seattle.