Spring has sprung

(March 20, 2012) The four seasons are determined by changing sunlight which is determined by how our planet orbits the Sun and the tilt of its axis. Today is the first day of spring here, although unseasonably it feels almost like early summer.

On the first day of spring — the vernal equinox — day and night are each about 12 hours long (with the actual time of equal day and night, in the Northern Hemisphere, occurring a few days before the vernal equinox). The Sun crosses the celestial equator going northward; it rises exactly due east and sets exactly due west.