MINNEAPOLIS (WCCO) – Thursday marks the first day of spring. But is it meteorological spring or astronomical spring?
Keeping the two straight can be tricky.
March 1 is the beginning of meteorological spring.
Meteorologists break down the seasons into groupings of three months. Doing so allows them to easily calculate weather data based on monthly statistics.
That information is then useful for various fields, ranging from farming to commerce.
— WCCO – CBS Minnesota (@WCCO) March 1, 2018
When’s astronomical spring?
That comes on March 20 during the vernal – or spring – equinox, when the sun passes directly over the equator. (That’ll happen exactly at 11:15 a.m. Central Time.)
Astronomical seasons are based on the Earth’s rotation around the sun. But due to the planet’s elliptical orbit, the lengths of astronomic seasons vary, between 89 days and 93 days.
As such, astronomical seasons are difficult for researchers to use when comparing one year’s weather data with that of another.
This difficulty in calculation is the reason scientists use created meteorological seasons.
When do we spring ahead?
That happens on March 11, a Sunday.
Be sure to set your clocks ahead an hour.