WEST MICHIGAN — Equinoxes come twice a year, once in the Spring and once in the Fall. The Spring Equinox is called the Vernal Equinox. This is when the Earth's axis is tilted neither toward nor away from the sun, which results in 'nearly' equal amount of daylight and darkness at all latitudes.
This year's Vernal Equinox occurs at 5:24 P.M. on March 20, 2023.
At the the equator, the sun is directly overhead at noon on these equinoxes. The close to equal hours of day and night is due to refraction of sunlight or a bending of the light's rays that causes the sun to appear above the horizon when the actual position of the sun is below the horizon. According to the National Weather Service, the days become a little longer at the higher latitudes, because the sun takes longer to rise and set, therefore, on the equinox and for several days before and after the equinox, the length of day will range from about 12 hours and six and one-half minutes at the equator, to 12 hours and 8 minutes at 30 degrees latitude, to 12 hours and 16 minutes at 60 degrees latitude.
West Michigan sits at about 42 degrees latitude, which puts us at 12 hours and 8 minutes and 30 seconds.
Technically speaking, Grand Rapids experienced the equinox early, on Friday March 17. The sunrise time for Friday was 7:51 A.M. and the sunset time was 7:51 P.M. creating an exact 12 hours of daylight. This is due to how we measure sunsets and sunrises. A sunrise is measured by when the top of the sun disc crosses the threshold above the horizon, and sunsets are measured when the disc crosses the threshold below the horizon.
Our local variation is due to our placement within the Eastern Time Zone and elevation, which can change when the sun disc crosses the thresholds, hence the amount of daylight we receive.
The National Weather Service mapped out the Equinoxes through 2030.