As we continue into the heart of the winter season, there is more to look forward to besides the continued cold days ahead. Contrary to what you may believe, our nights do not get shorter the deeper we get into winter. They do so up to a point, and we call that point the winter solstice. However, after that we actually begin to GAIN our daylight back all the way up to the summer solstice in June.
We define the winter solstice as the first day of astronomical winter. It also marks the shortest day and longest night of the year, but the length of our days and nights are always changing. Why do we see these changes? It’s all a product of our earth’s path around the sun, and the earth’s tilt on its axis.
The reason we have different lengths of night and day throughout the year is because of earth’s tilt toward and away from the sun. During the start of northern hemisphere summer on the June solstice, the earth is tilted directly towards the sun, and during northern hemisphere winter on the December solstice, the earth is tilted directly away from the sun as shown in the image above.
With earth being tilted away from the sun in northern hemisphere winter, each rotation of Earth on its axis sees less light and more night than it does when it’s tilted toward the sun in northern hemisphere summer. Up until the winter solstice, as we make that transition from summer to winter, we lose daylight, our sunsets are earlier, and our days get shorter. But there is good news…
After the winter solstice, the earth becomes less and less tilted away from the Sun, and we’re already seeing the effects. That combined with its always changing path in orbit around the Sun, our days become longer and the sun begins to set later. Woo!
PLUS: Not only do we see an increase in daylight after this point, but from the winter solstice on until the spring equinox, we’re gaining daylight at a faster rate each day. The way it looks on a graph represents it as a logarithmic bell curve, which means it’s not a straight line at an even pace.
On January 4th we officially started to gain at least 1 minute of daylight with each passing day, and by the 22nd of this month we will be gaining at least 2 minutes of daylight.
Why do we see this gradual increase and decrease throughout the year?
This discrepancy happens due to earth’s orbit around the sun not being a perfect circle. It’s an ellipse. This causes earth to be closer to the sun at different points of the year. Even though we’re tilted the farthest away from the sun in the winter, we’re also at our closest point to the sun in our orbit during this time, which causes the earth to move slightly faster due to a stronger gravitational pull.
Did you know? Perihelion is when the Earth passes the closest to the Sun in its orbit. This already occurred for Rochester on January 2nd, 2021 at 8:50 am.
After the Spring equinox, our sun continues to set later, (plus we set the clocks back 1 whole hour), but we’re still gaining daylight. It’s just at a slower rate each day. The farther we get from the sun, the more we become tilted towards it. That means brighter days, and slowly but surely, warmer days will are eventually ahead.
~Meteorologist Christine Gregory