Spring starts a little earlier than usual this year.

Tuesday, March 19 at 11:06 p.m. EDT marks the vernal equinox for the Northern Hemisphere, when the Sun is directly over the equator and its energy is in balance between the Northern and Southern Hemispheres. according to the National Weather Service.

In most years the season usually changes on March 20th or 21st. So why is spring starting a few hours earlier in 2024?

First day of spring 2024

The first day of spring is March 19th because 2024 is a leap year. Leap years are caused by the rotation of the Earth. There are 365 days in a year, but technically it takes the Earth a little longer to orbit the sun.

Accordingly, it takes the Earth 365 days, 5 hours, 48 ​​minutes and 46 seconds – or 365.2422 days – to completely orbit the sun NASA. These additional hours are removed from the calendar in most years. But once every four years An additional day is added to February So that the calendar and the seasons don’t get out of sync. If this doesn’t happen, the extra hours would add up over time and the seasons would change.

These leap years cause the first day of spring to occur earlier than normal.

In 2020, another leap year, the first day of spring was also on March 19, with the spring equinox occurring at 11:50 p.m Earliest first day of spring since 1896.

But the spring equinox in 2024 did it. Since spring begins even earlier at 11:06 p.m. ET, all time zones in the continental US experience the first day of spring on the 19th – at 10:06 p.m. in the Central Time Zone and 9:06 p.m. Mountain Time and 8:06 p.m Pacific time.

In the next leap year, 2028, spring begins again on March 19th. And until 2103, spring will begin earlier and earlier on March 19 each leap year.

In 2025, which is not a leap year, the vernal equinox will occur on March 20 at 5:01 a.m. EDT, and in 2026 it will occur on March 20 at 10:46 a.m. EDT. according to the National Weather Service.

What is the Spring Equinox?

Marked by either an equinox or a solstice, the seasons occur because the Earth rotates on an axis, so different parts of the planet are more or less exposed to the sun as it orbits the star throughout the year.

Spring and fall are marked by an equinox, which means “same night” in Latin. The sun passes directly over the equator at the equinox and there are approximately equal 12 hours of daylight and 12 hours of night. NASA explains.

During the vernal equinox, which marks spring in the Northern Hemisphere, the Southern Hemisphere experiences its autumnal equinox, which ushers in fall for this part of the world.

The autumnal equinox usually occurs on September 22nd or 23rd in the Northern Hemisphere.

During the Solstices that mark summer and winter, the Earth reaches the greatest angles of its axis. Typically, the summer solstice occurs on June 20 or 21 in the Northern Hemisphere because this area of ​​the Earth is tilted toward the sun. The opposite happens on December 21st or 22nd with the winter solstice.

Meteorological spring

To make things even more confusing, meteorologists assume a different system for the seasons. For weather forecasters, spring begins on March 1st, when the climate typically begins to turn more spring-like in most areas. Meteorological summer begins on June 1st, meteorological autumn begins on September 1st and meteorological winter begins on December 1st.

With this method, the length of the seasons is more consistent. In non-leap years they are every 90 to 92 days. NWS explains.

But the astronomical seasons that follow the equinoxes and solstices are not so consistent. According to the Old Farmers’ Almanac, spring has 92,771 days, summer has 93,641 days, fall has 89,834 days, and winter has 88,994 days.

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