Why is Monday considered spring? The vernal equinox, explained [View all]

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'Here in the northern hemisphere, spring in the form of the vernal equinox is scheduled to start Monday at 6:29 a.m. Although there’s still snow on the ground and cold weather in the forecast, one can’t deny the new season has arrived.

Meteorologists start spring after the coldest 90 days of the year, so we began it on March 1st. But astronomical spring arrives when the sun reaches a certain height over the equatoreach year. This is typically what most folks celebrate as spring’s arrival.

While nearly everyone knows spring arrives around March 20, what’s actually occurring in terms of the relationship between the earth and the sun still isn’t universally understood.

On both the vernal and autumnal equinoxes, the sun will be directly overhead at noon at some place along the equator of our planet. This year, the first of these two occurrences happens at 6:29 a.m Eastern Standard Time on March 20. Basically, if you were in central Africa and looked up at noon, the sun would be directly above your head, forming a 90-degree angle with the ground. On Friday, Sept. 22, at 4:02 p.m., the same thing will occur at a different spot along the equator to begin the fall season.'>>>

https://www.bostonglobe.com/metro/2017/03/19/why-monday-considered-spring-the-vernal-equinox-explained/4QpSoRlVS2I3KMlAofZcII/story.html