It can sometimes be confusing when we talk about Meteorological Spring vs. the Spring Equinox.
Meteorological Spring (and all Meteorological “seasons”) are for record-keeping purposes. They start on the first day of a month. Meteorological Spring starts March 1, Summer starts June 1, Autumn starts September 1, and Winter starts December 1. This allows us to keep season records consistent from year to year.
The spring, or vernal, equinox is often thought of as the “official” start to spring. This year, that occurs March 20 at 6:29 AM. It signals earlier sunrises and later sunsets. An equinox is an astrological event, meaning it measures movement of objects in outer space.
The Earth’s axis is tilted about 23.5º and seasons are controlled by our relation to the sun. The equinox signals neither one hemisphere nor the other is getting more direct sunlight – they’re both even. That also means that night and day are approximately equal which is what the word “equinox” literally means.