Thursday is the first day of spring, or the vernal equinox, in the Northern Hemisphere. During an equinox, the center of the sun is on the same plane as the equator. After the vernal equinox in March, the Northern Hemisphere tilts toward the sun until the June solstice, when the sun begins to migrate back south.

Spring Equinox is rapidly approaching. When is the first day of spring? What we know about when spring starts, winter ends, summer solstice and more.