Dear Tom,
What is the reasoning behind “meteorological” seasons as opposed to “astronomical” seasons?
Philip Bechen Vernon Hills
Dear Philip,
With meteorological spring beginning Sunday, it seems like a good time to address this frequently asked question. Astronomical seasons are defined by the spring and fall equinoxes and the summer and winter solstices. However, those begin and end dates vary from year to year. That’s why meteorologists prefer to use four three-month meteorological seasons. In the Northern Hemisphere, June, July, and August define meteorological summer, while meteorological winter is made up of December, January, and February. The remaining six months define meteorological spring and fall. Since climate records are kept on a monthly basis, defining a season in terms of three complete months makes comparisons and rankings an easy task.