The fall equinox, the Northern Hemisphere’s first tentative tilt into autumn, is Saturday.
It marks the astronomical end of the hottest, longest days of the year, and is the universe’s promise that cooler weather is on the way.
At the moment of equinox, the Earth’s axis leans neither toward or away from the sun — a parity that produces a nearly equal day and night.
“For us in the Northern Hemisphere, the sun is rising later now, and nightfall comes sooner,” said Deborah Byrd, editor-in-chief of the online magazine Earth and Sky. “We’re enjoying the cooler days of autumn.”
But in South Florida, the onset of fall-like temperatures is still at least a month away.
The average daytime high in West Palm Beach doesn’t dip below 85 degrees until Oct. 20, with overnight lows remaining in the 70s until Oct. 27 when the normal finally dips to 69 degrees.
And even then, the difference between the warmest and coldest periods of the year in South Florida can be just 25 degrees, according to the book Florida Weather, which was co-authored by Florida Climatologist David Zierden.
“A source of frequent complaint among northern migrants to Florida is its lack of distinct seasons,” the book notes.
In Chicago, Cleveland and New York City, there is a difference of approximately 70 degrees between the average maximum temperature and the average minimum temperature.
This week, the difference between the daytime high and overnight low in West Palm Beach was just 12 degrees with Monday reaching a searing 91 degrees and this morning bottoming out at an unofficial 79 degrees.
An area of high pressure over the state should keep the temperatures above normal into the weekend. The normal high this time of year in West Palm Beach is 88 degrees, with a normal overnight low of 75 degrees.