Winter is here — the meteorological winter, that is. If you’re thinking, “I thought winter began on Dec. 21,” you’re not wrong.
The astronomical winter begins on Dec. 21, which is separate from the meteorological winter that begins on Dec. 1.
What Are Meteorological Seasons?
Meteorologists and climatologists break the seasons down into groupings of three months based on the annual temperature cycle. For example, with winter being the coldest time of the year, the meteorological winter includes December, January, and February.
Meteorological Season Breakdown:
- Winter: December, January, February
- Spring: March, April, May
- Summer: June, July August
- Fall: September, October, November
Although March (and sometimes April, too) can deliver chilly temperatures and snow, it’s technically a spring month in terms of climatology.
What Are Astronomical Seasons?
The astronomical calendar has nothing to do with temperature, but rather the natural rotation of Earth around the sun. We then define the seasons with two solstices and two equinoxes.
Equinoxes mark the times when the sun passes directly above the equator, which happens in the spring and fall.
Astronomical Season Breakdown (Northern Hemisphere):
- Winter Solstice: December 21
- Vernal or Spring Equinox: March 21
- Summer Solstice: June 21
- Autumnal Equinox: September 22
The seasons are reversed, but occur on the same dates in the Southern Hemisphere, meaning summer begins on December 21 and winter begins on June 21.
What To Expect This Meteorological Winter
For the upcoming winter season, most models and forecasters predict less snow than average and milder conditions than normal. However, the word “mild” doesn’t cancel out the potential for an occasional snow storm.
Climate predictions from the National Weather Service show wetter and cooler conditions in the northwest, closer to Canada. The consensus for the east is less cold and less snow than usual.
Predicting the next three months of weather is like betting odds. We can use data to make our best assumptions, but there’s always room for an unexpected result. Tomorrow.io will keep you updated. Stay tuned!