Wednesday’s the winter solstice, but is it the best way to define winter?

JOE MARTUCCI Press Meteorologist

Four seasons, three ways to define them.

The spring, summer, fall and winter you see on most calendars start around the 20th of March, June, September and December, respectively. They’re called astronomical seasons.

<p>Astronomical seasons are based upon when the sun's most direct rays reach the Tropical of Cancer (Northern Hemisphere summer) or Tropic of Capricorn (Northern Hemisphere winter). </p>

AccuWeather, provided

Astronomical seasons are based upon when the sun's most direct rays reach the Tropical of Cancer (Northern Hemisphere summer) or Tropic of Capricorn (Northern Hemisphere winter). 

Astronomical seasons have roots dating to the Julian calendar used by the ancient Romans, according to NASA. They are based on the position of the sun’s most direct rays between the Tropics of Cancer and Capricorn (about 23.5 degrees north and south latitude, respectively). When the sun is directly over the Tropic of Cancer, summer begins in the Northern Hemisphere, and when the sun is over the Tropic of Capricorn, summer begins in the Southern Hemisphere.

However, some argue that seasons shouldn’t begin on the longest or shortest day. Weather doesn’t quite fit into as neat a pattern as the calendar would have you believe.

There are two other methods used in the United States to define the changes seen around us: solar seasons and climatological seasons. Both are similar to astronomical seasons in that there is a spring, summer, fall and winter. They each also are roughly a quarter of the year long and signal a change in the world around us.

Climatological seasons use the average weather of the year to define when the seasons are. For most places in the United States, June, July and August are the hottest three months of the year, so those are referred to as climatological summer, even though there are some exceptions, like the immediate West Coast, South Texas and parts of Alaska and Hawaii.

On the opposite end, climatological winter runs from December through February. Once you determine winter and summer, spring and fall fit the gaps in between.

<p>Leaves begin to change autumnal colors along the bike path off Wabash Avenue, in Linwood, N.J., Thursday, Oct. 7, 2021. (VERNON OGRODNEK, FOR THE PRESS)</p>

VERNON OGRODNEK FOR THE PRESS

Leaves begin to change autumnal colors along the bike path off Wabash Avenue, in Linwood, N.J., Thursday, Oct. 7, 2021. (VERNON OGRODNEK, FOR THE PRESS)

Climatological terms are popular in the weather community and are increasingly used by meteorologists. In fact, the Australian Bureau of Meteorology defines the seasons using the climatological definitions. Since Australia is in the Southern Hemisphere, its seasons are in reverse order. Summer is December through February, while winter is June through August.

The advantage climatological seasons have over astronomical seasons is that they always start and end on the same day. Climatological summer begins on June 1 every year and ends on Aug. 31. For most places, this corresponds with the rising and falling of temperatures, which many first think of when they think of seasons.

On the other hand, not all locations fit nicely into the averages used for climatological seasons. Along the coast in Santa Monica, California, it’s actually July through September that are the warmest three months of the year. October, at 64.7 degrees, has a warmer average temperature than June, which is 63.4 degrees, according to the National Oceanic and Atmospheric Administration. Detractors can also point to the fact that astronomical seasons are defined by celestial events, not earthly ones, and therefore impact the entire Earth at the exact same time.

Solar seasons are based on celestial events, buffering it from worldly interactions with the climate. Here, the seasons are defined by the length of daylight, divided into quarters. Solar summer is the roughly 91-day period with the most possible daylight, while solar winter is the 91-day period of shortest possible daylight.

Using summer as the example, the solar definition of the season goes from roughly May 6 to Aug. 5, depending on latitude north or south of the equator. At the Jersey Shore in Atlantic City, the length of day is no shorter than 14 hours and 2 minutes during this time. Daylight then peaks at 14 hours and 56 minutes during the summer solstice, known as midsummer. Solar winter then runs from roughly Nov. 7 to Feb. 6.

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Like astronomical seasons, solar seasons are based on celestial events, so all locations experience the same season equally. However, one may argue that solar seasons do a better job of defining the seasons based on the sun than astronomical seasons. Taking summer for example, astronomical summer begins on the longest day of the year, the solstice, with all days in the season being longer. On the other hand, solar seasons use the equinoxes and solstices as midway points.

Detractors may argue that solar seasons don’t accurately represent the weather of the season they’re in. When solar summer ends around Aug. 5, the immediate West Coast of the United States, South Texas and other places across the globe are in the midst of their warmest month of the year.

When people think of seasons, many think of the weather that comes along with it, making climatological seasons the preferred option. Others may prefer the seasons to be based on the sun, in which case astronomical or solar seasons would be the preferred choice. These three methods evolved to define the four seasons based on how people experience the changes in the calendar.

<p>People enjoy a warm spring day Tuesday at Birch Grove Park in Northfield, N.J.</p>

Edward Lea, Staff Photographer

People enjoy a warm spring day Tuesday at Birch Grove Park in Northfield, N.J.


<p>Brad Heffley, a crew supervisor at Birch Grove Park in Northfield, tosses fish into the lake Tuesday.</p>

Edward Lea, Staff Photographer

Brad Heffley, a crew supervisor at Birch Grove Park in Northfield, tosses fish into the lake Tuesday.


<p>Ducks cruise the water at Birch Grove.</p>

Edward Lea, Staff Photographer

Ducks cruise the water at Birch Grove.


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