First Day of Seasons: 2016

When Do the Seasons of the Year Begin?

 

Listed below are the equinox and solstice dates and times, based on the Eastern Time Zone (ET). Adjust to your time zone. Note that an almanac is an astronomical “calendar of the heavens;” these dates are not based on local meteorology.
For readers of The Old Farmer’s Almanac, these dates mark the start of the spring, summer, autumn, and winter seasons in the Northern Hemisphere.

Seasons of 2016:
SPRING EQUINOX	March 20, 12:30 AM EDT
SUMMER SOLSTICE	June 20, 6:34 P.M. EDT
FALL EQUINOX	September 22, 10:21 A.M. EDT
WINTER SOLSTICE	December 21, 5:44 A.M. EST

Seasons of 2017:
SPRING EQUINOX	March 20, 6:29 A.M. EDT
SUMMER SOLSTICE	June 21, 12:24 A.M. EDT
FALL EQUINOX	September 22, 4:02 P.M. EDT
WINTER SOLSTICE	December 21, 11:28 A.M. EST

Why Do the Seasons Change?

The four seasons are determined by shifting sunlight (not heat!)—which is determined by how our planet orbits the Sun and the tilt of its axis.

Photo Credit: NASA

• On the vernal equinox, day and night are each approximately 12 hours long (with the actual time of equal day and night, in the Northern Hemisphere, occurring a few days before the vernal equinox). The Sun crosses the celestial equator going northward; it rises exactly due east and sets exactly due west.
  
• On the summer solstice, we enjoy the most daylight of the calendar year. The Sun reaches its most northern point in the sky at local noon. After this date, the days start getting “shorter,” i.e., the length of daylight starts to decrease.
  
• On the autumnal equinox, day and night are each about 12 hours long (with the actual time of equal day and night, in the Northern Hemisphere, occurring a few days after the autumnal equinox). The Sun crosses the celestial equator going southward; it rises exactly due east and sets exactly due west.
  
• The winter solstice is the “shortest day” of the year, meaning the least amount of sunlight. The Sun reaches its most southern point in the sky at local noon. After this date, the days start getting “longer,” i.e., the amount of daylight begins to increase.