It’s the First Day of Spring
The March equinox occurs at 16:15 UTC. The Sun will shine directly on the equator and there will be nearly equal amounts of day and night throughout the world. This is also the first day of spring (vernal equinox) in the Northern Hemisphere and the first day of fall (autumnal equinox) in the Southern Hemisphere.
What effect does Earth’s axial tilt have?
In 2018, this is on March 20, at 16:15 UTC. For locations that are at more than 10 hours behind UTC, it was on March 19. This is because of the time zone difference.