ROCHESTER, N.Y. (WROC) — While everyone changes seasons, Rochester and Upstate New York along with much of the northern half of the country truly experience the change of season. Here we dive into those differences and why we see them. The astronomical reason we have seasons is because of earth’s path and the changing tilt towards and away from the sun.
Let’s break it down:
Our earth makes one full revolution, or trip around the sun in roughly 365 days. To be exact, it actually takes the earth 365.24 days to make its full trip, which is why we have a leap year that accounts for the extra day we accumulate every four years.
Fun Fact: The reason we have seasons is NOT based on the distance away from the sun. It’s actually based on the tilt of earth’s axis. During the summer, we’re actually farther away from the sun than we are in the winter.
This seems counterintuitive, but the distance the earth is relative to the sun has no significant effect on our climate. As earth revolves around the sun, the tilt of the earth changes and is what provides us with the differences in seasons and the different amounts of of day and night we receive throughout the year. The changing distances from the sun are too small to make any significant difference.
Solstice (Summer & Winter)
When the earth is tilted at its maximum towards the sun, it’s called the summer solstice. This is the day where the sun is at its highest in the sky, and we receive the longest amount of day with the shortest amount of night. The winter solstice is the day where we receive the shortest amount of day and the longest duration of night; the sun being at its lowest in the sky.
Equinox (Vernal & Autumnal)
Since this tilt towards and away from the sun happens very gradually over the course of the entire year, there must be two points during that time period (between when the earth is tilted away and towards the sun) where the earth’s tilt is aligned in such a way that we receive equal parts day and night; a full 12 hours each.
NOTE: The time of day is measured by when the first bit of light from the sun is visible (and disappears). Since earth’s atmosphere refracts light, the suns top crescent can be seen a few minutes before actual sunrise and a few minutes after sunset. This means that the day/night split of 12 hours in spring happens a few days before the equinox and in the fall, a few days after the equinox.
When this occurs its referred to as an equinox. This occurs twice a year both beginning the start of the fall (or autumnal) equinox, and spring (vernal) equinox. The term equinox comes from the Latin words, aequus meaning equal, and nox meaning night. At solar noon during this time, the sun will be directly overhead providing us with equal parts day and night.
. . .
For more details about the differences between solstices and equinoxes, click HERE.