In the Southern Hemisphere, the seasons are reversed but begin on the same dates. The vernal, or spring, equinox usually happens on or around March 21 the summer solstice falls on or around June 21 and the autumnal equinox happens on or around Sept. Under those circumstances, astronomical winter and the solstice occur in the Northern Hemisphere on Tuesday, Dec. So meteorological winter includes December, January and February spring includes March, April, and May summer is in June, July and August and meteorological fall includes September, October and November.Īstronomical observations of the seasons based on solstices and equinoxes are determined by the Earth’s tilt and the sun’s alignment when it passes directly above the equator.
“The natural rotation of Earth around the sun forms the basis for the astronomical calendar, in which we define seasons with two solstices and two equinoxes,” the National Oceanic and Atmospheric Administration says.Įxamining the differences between astronomical and meteorological seasons, NOAA notes, “Meteorologists and climatologists break the seasons down into groupings of three months based on the annual temperature cycle, as well as our calendar.” Now, it might be just as unthinkable that December marks the first day of winter.īut it depends on whose information you’re referencing.
It was a radical notion when Copernicus declared that the Earth rotates around the sun.
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