Thursday, December 1 marked the official start of the meteorological winter season.
You may be asking, “I thought winter didn’t start until the winter solstice in late December?”
While that is technically true when thinking about how the Earth revolves around the sun, meteorologists and climatologists combine the calendar and another parameter to judge the seasons: temperatures.
When talking temperatures, we often think of winter as being the coldest time of year and summer being the warmest, with both separated by the transition seasons of spring and fall.
This thought serves as a baseline for meteorological seasons, categorizing each one according to the annual temperature cycle:
- Meteorological Winter: December 1 - February 28 (or 29 depending on if it’s a leap year)
- Meteorological Spring: March 1 - May 31
- Meteorological Summer: June 1 - August 31
- Meteorological Fall: September 1 - November 30
According to the National Oceanic and Atmospheric Administration (NOAA), meteorological observations and forecasting essentially helped create this concept of seasons.
While the length of each astronomical season varies a bit, the durations of meteorological seasons are generally more uniform.
This makes it easier to calculate monthly and seasonal statistics, which come in handy for a variety of reasons, including weather and climate!