Vernal Equinox Marks Start Of Astronomical Spring In the Northern Hemisphere

Today is the vernal equinox, the first day of spring for Earth’s northern hemisphere. At this point in the planet’s annual orbit, the sun appears directly over the equator, producing essentially the same amount of time in daylight and darkness over today’s 24 hours. Then, for the northern half of the planet, daylight hours steadily increase until the longest day of the year, the summer solstice, in June. Time in daylight will then start to decline again, eventually reaching the autumnal equinox this fall.