Spring is just around the corner, at least officially.
The vernal equinox arrives on Tuesday, marking the beginning of spring in the Northern Hemisphere.
But what does that actually mean? Here’s what you need to know about how to divide the year using the Earth’s orbit.
What is the vernal equinox?
As the Earth moves around the Sun, it moves diagonally.
For most of the year, the Earth’s axis is tilted toward or away from the sun. That means the sun’s warmth and light hits the northern and southern halves of the Earth unevenly.
During the vernal equinox, the Earth’s axis and its orbit align, and both hemispheres receive the same amount of sunlight.
The word vernal equinox comes from two Latin words meaning equality and night. That’s because on the vernal equinox, day and night last approximately the same amount of time. However, depending on where you are on the planet, you may get a few extra minutes.
The spring equinox in the Northern Hemisphere occurs between March 19th and 21st, depending on the year. That autumnal equinox, or fall equinox, can arrive between September 21st and 24th.
What is the summer solstice?
The summer solstice marks the time of year when the Earth tilts most toward or away from the sun. This means that each hemisphere receives very different amounts of sunlight, making day and night the most uneven.
At the summer solstice in the Northern Hemisphere, the top half of the Earth tilts toward the sun, resulting in the longest day and shortest night of the year. This summer solstice falls between June 20th and 22nd.
Meanwhile, at the winter solstice, the northern hemisphere moves away from the sun, resulting in the shortest day and longest night of the year. The winter solstice falls between December 20th and 23rd.
What is the difference between meteorological seasons and astronomical seasons?
These are just two different ways to divide the year.
Weather seasons are defined by the weather. The year is divided into three-month seasons based on the annual temperature cycle. According to this calendar, spring begins on March 1st, summer on June 1st, autumn on September 1st, and winter on December 1st.
Astronomical seasons are determined by how the Earth moves around the sun.
It marks the vernal equinox and the beginning of autumn. The summer and winter solstices begin.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Education Media Group. AP is solely responsible for all content.
