Equinoxes and Solstices

by Matt Oltersdorf 2003 10 26 18:10 UTC
back to Java for Astronomy


 
Year:

Spring:

Summer:

Autumn:

Winter:

From    to  

The algorithm used in my JavaScript is valid for the years 1000 to 3000, and for several centuries after 3000 with errors still quite small.

Spring equinox:
is the beginning of spring (vernal equinox). It occurs on March 19, 20 or 21 in the Northern Hemisphere.

For the years from 1583 to 3082 there are 100 Spring equinoxes on March 19, 1032 on March 20, and 368 on on March 21.

Summer solstice:
is the beginning of summer. It occurs on June 21 or 22 in the Northern Hemisphere.

Autumnal equinox:
is the beginning of autumn. It occurs on Sept. 22 or 23 in the Northern Hemisphere.

Winter solstice:
is the beginning of winter. It occurs on on Dec. 21 or 22 in the Northern Hemisphere.

 

 

Date of spring equinox frequencies per century (2000-2099 to 2900-2999):

Total 2000 to 2999:

 
Mar 19 Mar 20 Mar 21
94 723 183

Total 3000 to 3999:

 
Mar 19 Mar 20 Mar 21
72 699 229

Total 4000 to 4999:

 
Mar 19 Mar 20 Mar 21
86 720 194

Last Modified: