First Day Of Winter 2016: Winter Solstice Marks Start Of Season, But For Meteorologists It Begun Weeks Ago

For those already worn down by the freezing temperatures, Wednesday brings some bad news: winter has only just begun. The coldest season of the year officially got started at 5:44 a.m. EST, Dec. 21, in line with the winter solstice, the time when the North Pole is titled farthest away from the sun. Yet calculating the first day of winter isn’t quite that simple.

The four seasons are determined on the calendar by the position of the sun relative to the Earth, but not temperatures. Thus, while Wednesday heralded the start of astronomical winter in the Northern Hemisphere, from a meteorological standpoint, it has long since been underway.

Meteorologists calculate seasons based on average temperatures and consider December, January and February the coldest months of the year. So, it may be good news for those being battered by the arctic blast that a fair chunk of winter has already been survived, with winter having begun Dec. 1.

It’s not all good news, though. For those in the eastern half of the United States, the coldest day of the year is yet to come. From the date of the winter solstice and the Earth’s farthest point from the sun it takes a while for the cold air to truly settle. It means that the coldest day of the year usually occurs around mid-January on the East Coast, even though in the west of the United States it has historically been coldest in December.

But while it may be cold for a while yet, at least it’s going to start getting lighter. What winter solstice does definitively mark is the shortest day of the year in terms of daylight. From here on out, the days will begin lengthening and it won’t be too long before people will again be able to leave the office with the sun still shining.

For those wondering when spring is going to arrive, again, it depends on who you ask. Meteorologically speaking, it gets going on March 1 — that’s when the coldest of the temperatures should be in the rearview mirror. But, for astronomers and the calendar, the season will begin on March 20 with the Spring Equinox, marking when the sun crosses the celestial equator.