The shortest day of the year is descending on the Northern Hemisphere. Here’s what to know
Yes, the darkest day of the year is here, but that means brighter days lie ahead.
Sunday is the shortest day of the year north of the equator, where the solstice marks the start of astronomical winter. It’s the opposite in the southern hemisphere, where it’s the longest day of the year and summer is about to begin.
The word “solstice” comes from the Latin words “sol” for sun and “stitium” which can mean “pause” or “stop”. The solstice marks the end of the sun’s annual march up or down in the sky. The winter solstice is when the sun makes its shortest and lowest arc. Good news for sun lovers: the climb then begins again and the days will get a little longer each day until the end of June.
People have marked the solstices for ages with celebrations and monuments such as Stonehenge, which was designed to align with the paths of the sun at the solstices. But what is happening in the skies? Here’s what you need to know about Earth’s orbit.
What is the solstice?
When Earth moves around the sun, it does so at an angle, causing the sun’s heat and light to fall unevenly on the northern and southern halves of the planet for most of the year.
The solstices mark the times when the Earth’s tilt toward or away from the sun is at its maximum. This means that the hemispheres receive very different amounts of sunlight – and that the days and nights are the most unequal.
At the northern hemisphere’s winter solstice, the upper half of Earth is farthest from the sun, leading to the shortest day and longest night of the year. The winter solstice can fall between December 20 and 23 – this year it’s the 21st.
The opposite occurs during the Northern Hemisphere’s summer solstice: the upper half of the Earth is tilted toward the sun, creating the longest day and shortest night of the year. This solstice falls between June 20 and 22.
What is the equinox?
During the equinox, Earth’s axis and orbit align so that both hemispheres receive an equal amount of sunlight.
The word equinox comes from two Latin words meaning equal and night. Indeed, at the equinox, day and night last almost the same length, although you may have a few extra minutes, depending on where you are on the planet.oo
The northern hemisphere’s autumnal – or fall – equinox can occur between September 21 and 24, depending on the year. Its spring – or vernal – equinox can arrive between March 19 and 21.
What is the difference between meteorological and astronomical seasons?
These are just two different ways of dividing the year.
While astronomical seasons depend on how the Earth moves around the sun, meteorological seasons are defined by the weather. Meteorologists break the year into three-month seasons based on annual temperature cycles. According to this calendar, spring begins on March 1, summer on June 1, autumn on September 1, and winter on December 1.
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