Some math for dating seasons

[scrupul0us]

I've been all over google trying to find soem calculations for figuring out the first day of Spring, Summer, Autumn, Fall, and Winter but cannot find anything! Can anyone assist me?

Thanks

[bpat1434]

You could always make one on your own:

Length of Seasons
Winter 88.994 days
Spring 92.758 days
Summer 93.651 days
Autumn 89.842 days

Now, Spring starts on May 20th at 7:33 am EST in the Northern Hemisphere (12:33 GMT).

That's a pretty good start.

~Brett

[mtmosier]

First thing to do is determine which first day of the seasons you want. Different countries and hemispheres use different dates. Wikipedia discusses it.

Assuming you want seasons based on the solstices and equinoxes, then the only hint at equations I could find where by Jean Meeus in a book entitled "Astronomical Algorithms". You can buy the book of course if you want. This site has an online calculator based on formulas in the book, but no code. This program claims to use the formulas from Astronomical Algorithms to calculate the solstices and equinoxes. It's in visual c, but the calculations look very simple.