Published on 02/26/09

When does spring begin?

By David Stooksbury
University of Georgia

When does spring begin? Well, it depends on whom you ask.

Most calendar makers list the first day of spring as the day of the vernal equinox, which occurs around March 20. This is referred to as astronomical spring.

Most atmospheric scientists, meteorologists and climatologists say it begins March 1. The National Weather Service uses March 1 as the beginning of spring for climate summary purposes. Dates for the beginning of the climatological seasons are March 1 for spring, June 1 for summer, September 1 for fall and December 1 for winter.

The dates for the beginning of the astronomical seasons are the vernal equinox (around March 20) for spring, the summer solstice (around June 21) for summer, the autumnal equinox (around September 22) for fall, and the winter solstice (around December 21) for winter.

Other ways of defining the seasons have been proposed. The one that is the most logical is to define the summer solstice as the midpoint of summer since the daylight is greatest then. The midpoint of winter is defined as the winter solstice since this is when the daylight is least. By this method, summer would be the six and half weeks before and after the summer solstice. Winter would be the six and half weeks before and after the winter solstice. The midpoint of spring would be the vernal equinox. For fall, it would be the autumnal equinox.

Other designations of spring include Good Friday or the start of the baseball season. My personal favorite is the Masters Tournament week in Augusta. Once the Masters is over, spring is usually here to stay in Georgia. Of course in Georgia, we can still have a dogwood or blackberry winter cold snap in late April or early May.

Regardless of which definition of the seasons one uses, spring in the Southeast is a season of transition. Early spring is characterized by wide swings in temperature with periods of very cold and very warm weather.

Freezes are common throughout Georgia during March. Freezes in late April do happen at times, especially in the northern half of Georgia. Snow and ice storms can happen in March, too, which has included a major blizzard in 1993 and an ice storm in the early 1970s.

David Emory Stooksbury is associate professor of Biological and Agricultural Engineering at University of Georgia's College of Agricultural and Environmental Sciences.