I have always thought winter weather begins weeks before the calendar agrees. The winter solstice officially changes the season at 3:12 a.m. PST Friday morning.
At that moment, the sun sits over the Tropic of Capricorn and the Earth's northern pole is tipped away from the sun. As seen from Portland, the sun will reach it's lowest southern point in the sky at 21 & 1/2 degrees on the horizon. The low angle will produce the longest and most spectacular sunrises and sunsets of the year, assuming we get to see. The shortest days of the year in terms of daylight hours are December 18-21st. Each day receives roughly 8.5 hours of sunlight minutes. Although the sun continues to rise later in the morning, sunset has already been occurring slightly later each evening. By February we will have gained enough daylight to produce warmer days with the average high warming back into the 50s. February is famous for a period of mild weather, often the first since the cold rains of December.
KGW Meteorologist Rod Hill