The 2023 vernal equinox, which marks the start of the season in the northern hemisphere, will take place on Monday, March 20th, rather than on March 21st as is often expected. do you see why
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This year, according to NASA, spring officially begins on Monday at 5:24 p.m. Quebec time.
What is an equinox?
The inclined earth takes one day and night to revolve around itself and one year to revolve around the sun.
The equinox corresponds to the time when the sun is highest in relation to the equator, i.e. at a point that is vertically above our heads. On this day, day and night have exactly the same number of hours, and the two hemispheres receive the same amount of sunshine.
A calendar problem
To measure days, months, and years, most of us use the Gregorian calendar, which divides a year into 12 months. In fact, however, the earth takes 365.2422 days to revolve around the sun. Each year therefore ends with a quarter day less than its actual length, hence the decision to have a 29-day month February every four years.
These variations also have the effect of changing the day of the equinox.
It will have to wait until 2102 for the vernal equinox to fall again on March 21st. The Autumnal Equinox is also affected and should not arrive until 2092 on September 21st.
What to expect for 2024?
For the first time since 1896, spring 2024 falls on March 19. It’s also one of those years when February will be a leap year, meaning it will have 29 days, shifting the equinox by an extra day.
“Consider July as a hot summer month to live in. If we never had a leap year, all those lost hours would add up to days, weeks, and even months, NASA has detailed. After a while, hundreds of years from now, July would become a cold winter month [pour l’hémisphère nord].”