We get a lot of questions from readers here at the Farmers’ Almanac, and we do our best to answer each one. This was a recent question about meteorological winter via Facebook:
Q: What’s the difference between meteorological winter and astronomical winter?
A: Meteorologists define “winter” as the three coldest months of the year: December, January, and February. So to them, winter begins on December 1st and ends on February 28th. The first day of meteorological spring is considered March 1st, with the three months of spring being March, April, and May.
Astronomers, on the other hand, determine winter by when the noontime Sun reaches its farthest point south in the sky; or when the Sun’s rays shine down from a point directly overhead as seen from the tropic of Capricorn (latitude 23.5 degrees south), known as the Winter Solstice. That happens on December 21 or 22, depending on the year. Astronomers call that the start of winter in the Northern Hemisphere, and it continues as such until the direct solar rays shine down on the equator at the vernal or spring equinox on March 20th.
In short, the seasons you are familiar with, by the calendar, are “astronomical,” and the months that your meteorologist chats about on the evening news are our “meteorological” seasons. We’ll greet meteorological spring on March 1st.
What do you think: should December 1 be the official start of winter and March 1st be the official start of spring? Share your thoughts in the comments below.