September 22nd, the mark of this years autumnal equinox, and for many, a reason to pull out their fall decorations as they cool down from the summer and wave off the appearance of the cold, snowy days of winter.
Mary Knapp, K-State Research and Extension, says the autumnal equinox marks the official start of autumn, and many believe it is the day that both the night and day are equal in length- twelve hours.
“The equinox is considered to be the day on which the geometric center of the sun is directly over the equator and stays above the horizon for twelve hours everywhere on Earth,” Knapp says.
She adds that though that is the belief, it’s not quite that simple, and says here in Manhattan the day that actually comes closest to day and night being equal in length is September 26, four days after the official equinox.
“The sun isn’t just a single point, and sunrise and sunset times are determined by the edge of the sun, not the center.”
Knapp says the farther you are from the equator, the bigger the difference in sunrise and sunset times as well as the actual point that the day and night are equal.
Knapp says while many believe that the autumnal equinox actually does mark the day where daytime and nighttime are both twelve hours, she says many also believe that September snow in Kansas is something that won’t happen- both of which, she says are wrong.
Knapp says the heaviest snows can actually come both early and late in the season because systems have more moisture available. She adds that, exactly that, happened in Western, KS in September of 1995.
“On September 20th, heavy snow of six to twelve inches snapped trees, power lines, and caused extensive damage to immature crops in northwest Kansas,” Knapp says. “Snow amounts ranged from twelve inches in McDonald to six inches near Goodland.”
Knapp adds that the snowfall was the heaviest on record for September. She says the snow continued in southwest Kansas as well, which marked the earliest snowfall on record for them.
“Two to three inches was common across the division. This was the earliest snowfall and the only September snow ever recorded at the Dodge City airport.”
While it is only September, and autumn is just getting started, don’t FALL into believing there is (S)no(W) chance it can snow this time of year.