March 20, 2017 – During the spring (vernal) and autumn (autumnal) equinoxes, the sun’s rays are directly over the equator. Equinox means “equal night” and day and night are about equal all over the world.
Due to the tilt of the earth’s axis, the sun’s rays are more directly over the Northern Hemisphere in the spring and summer, and directly over the Tropic of Cancer at the time of the Summer Solstice, which is June 20th at 9:24 PM PDT this year.
Because the Sacramento area lies about 38 degrees north of the equator, March 16th was actually closest to equal day/equal night in Sacramento.