The Seasons

Date and Time of the Start of Each Season

Vernal	Equinox	Summer	Solstice	Autumnal	Equinox	Winter	Solstice
Year-Month-Day	GMT	Year-Month-Day	GMT	Year-Month-Day	GMT	Year-Month-Day	GMT
2008-03-20	05:58	2008-06-21	00:00	2008-09-22	15:40	2008-12-21	12:02
2009-03-20	11:47	2009-06-21	05:48	2009-09-22	21:29	2009-12-21	17:51
2010-03-20	17:36	2010-06-21	11:36	2010-09-23	03:17	2010-12-21	23:41
2011-03-20	23:25	2011-06-21	17:24	2011-09-23	09:06	2011-12-22	05:30
2012-03-20	05:14	2012-06-20	23:12	2012-09-22	14:54	2012-12-21	11:20

GMT =Greenwich Meridian Time.  Lincoln is GMT - 6 hours when using Standard Time and -5 hours when using Daylight Savings Time. 

For example, the start of Spring in 2008 is March 20 at 05:58 GMT which is 0:58 CDST or 12:58 AM CDST

Season Definitions:
Vernal Equinox = Start of Spring
Autumnal Equinox = Start of Autumn or Fall
Winter Solstice = Start of Winter
Summer Solstice = Start of Summer