In 2021, the spring equinox occurs on Saturday, March 20. This event marks the astronomical first day of spring in the Northern Hemisphere. 

In the Northern Hemisphere, the spring equinox occurs when the Sun crosses the equator line, heading north in the sky. This event marks the start of spring in the northern half of the globe. After this date, the Northern Hemisphere begins to tilt toward the Sun, resulting in increasing daylight hours and warming temperatures. Hurray for sunshine!