Despite the recent resurgence of winter weather, I can feel how close spring is. Here in New Mexico, the roadrunners are frolicking, trees are budding, and I'm sowing lettuce seeds in my raised garden beds.

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.