First Day of Spring

The spring equinox, also called the vernal equinox in the northern hemisphere, is the midpoint between the shortest and longest days of the year (winter and summer solstices).  The date of the spring equinox is usually designed as the first day of spring. Since the equinox falls at a specific minute sometime during March 20, the following day, March 21, is sometimes called the first day of spring, or the first full day of spring.