Themes > Science > Earth Sciences > Hydrology, Meteorology, Climatology > Meteorology / Climatology > Seasons and Solstices

Why are there seasons? For many years, people pondered this same question, and it took humankind until the 1500s to finally figure it all out. The solution, it turns out, is as simple as the Earth orbiting the Sun. Almost every person born since the Civil War has known this since he (or she) was a child, but still, just because the Earth goes 'round the sun, this does not imply that seasons should necessarily occur; there's something a little more complex than just the orbit of the Earth involved. This section of the tutorial shall examine how it all works, and why, exactly, there are seasons.

A few terms you ought to know

Equinox
  • A time at which the days and nights are the same length around the world.
  • Occurs around March 21 and September 21 (but not necessarily on those dates).
  • Occurs when the Sun is directly over the equator.
  • Is either vernal (in the spring) or autumnal (in the fall).
Solstice
  • A time at which either day or night is the longest it will be during the year.
  • Occurs around June 21 and December 20 (but not necessarily on those dates).
  • Goes simply by winter or summer solstice.
  • Occurs when the sun is directly above 23.5 N latitude (Summer Solstice) or 23.5 S latitude (Winter Solstice).
  • Will allow one pole to have 24 hours of daylight, while the other pole has a 24 hour night.


Information provided by: http://vortex.plymouth.edu