In Search of Fall

Probably Florida’s most eagerly anticipated season. But when does it start? | Florida’s cycle Weather | Wet season | Dry season | Endless summer | Waiting for fall | Coolish winter | Spring drought | Hydrologic holidays

Intro - Anticipating fall

The long-awaited arrival of summer's end

By Robert V. Sobczak

It’s never a question of if, but when …

While sooner than latter is always preferred.

Fall is Florida’s most anticipated season

Fall is probably Florida’s most anticipated season. After a long summer stretch of endless heat and humidity punctuated by an uptick in tropical storms at the end (and just when it looks like fall with never arrive), the arrival of cooler and drier weather is a reason for celebration across the state.

Up North on the continent, Labor Day usual signals the reliable shift to crisper fall air. The conventional wisdom in south Florida is that fall is still 6-8 weeks away, or is it closer than we think?

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The clues are gradual at first, and quite subtle, making them easy to miss. Botanically, cypress lead they way as they slowly senesce, first to a duller shade of green and then a mix of browns and finally to gray – just bare branches – as the needles fall to the grown. Meteorologically, starting in early October, the summer afternoon rain machine sputters to a stop. Also working in the background is the steady drop in daylight hours and eventually the daylight savings one-hour shift. If you didn’t notice before, by 6 o’clock it’s getting dark.

fall
When the first official cold front arrives

It’s about this time two that the first true blue cold fronts arrives. Not quite cold enough to wear long pants, it might inspire a long sleeve shirt and possibly a thin fleece.

Fall has arrived, at long last!

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tidal

Two Floridas
One's mild and the other is less mild

How much colder is …

Naples from Gainesville, Florida?

Comparison of high and low air temperatures in Gainesville and Naples, FL

Answer: In terms of daytime lows dropping below 50 degrees, Gainesville has already recorded 15 compared to zero in Naples. In fact, there’s only been six nights in Naples that even dropped below 60 degrees. That’s not including wind chill. Nor does it factor in that you are also wearing shorts.

Interestingly, Naples and Gainesville are in the same neighborhood when looking at daytime highs. It’s the nighttime lows that separate them. But that’s splitting hairs really. Everywhere in Florida has a mild winter compared to most of the rest of the United States.

fall

Shift of the sun dial
And how the swamp responds

In case you forgot:

The swamp sun dial got set back on hour last night.

Swamp sun dial gets set back

The reason? In a nutshell it has something to do with keeping daylight hours aligned with normal working hours. Initially, turning the clocks back gives us more daylight in the morning. But that too will diminish as we approach the shortest day of the year on December 21st.

To be honest, for me the one hour change is much too abrupt. My strategy has always been to shift the clock back 15 minutes on Friday night, then another half hour on Saturday night, then take Sunday night off to let those forty five minutes soak in (in the same spirit as does a high-altitude mountain climber make base camp at 20,000 ft to acclimate to the low oxygen air) before proceeding with correcting for the final remaining 15 minutes on Monday night. And yes, if I were king for a day, I would grant everyone a week off of work to fully adjust.

As far as the natural world goes: Has anyone else noticed how instantaneously the cypress trees respond to the sudden one hour loss of light? As you are aware, it’s the decrease in light, not the onset of cold, that causes their needles to fall. The one hour drop off causes them to turn from green to gray virtually overnight.

The end of daylight saving has a startling effect on the trees

Not even the sun is immune! Sunsets over the gulf are much more frequent once daylight savings ends. Trust me, I’ve been at Naples Beach until close to 8 pm on many a summer day and never saw it set. (Presumably it never did.) Compare that to the winter where the sun sets – and beautifully I might add  like clockwork during the same time as in the summer it would be bright as could be day.

Sunsets are also more frequent
once Daylight Savings ends (as far as I can tell).

And last but not least: Is it me or does everyone suddenly grow taller (as judged by my shadow on the ground.) Who would have thought a swamp dial could be so strong?

fall

Very ripe on the vine
And how I got back into seasonal sync

You know fall has arrived Up North …

When the apples really start to crunch.

Fall is apple season in the Northeast

One fall long ago I visited my brother in the Hudson River Valley. I had just returned east after living a few years in the Sonoran Desert corner of the Great American Southwest studying (you guessed it) water.

The back story is that Arizona didn’t have any (water), or not much of it — with every drop being all the more precious because of its scarce state. Also conspicuously absent were “seasons.” Not that the natives wouldn’t scoff indignantly at my insinuation of seasonlessness: “Of course we have seasons!” was the usual rebuttal. Yes, I get it: the saguaros are less green in fall, or are the more green — one or the other, or maybe they were the same and other things changed. In a nutshell, I didn’t stay long enough to get into seasonal sync with the Southwest at the same time I lost sync with the old rhythms of the Northeast.

Opening my brother’s fridge, I was shocked: Apples were packed everywhere – up on the egg racks, behind the butter, in every unused drawer. It was fridge full of apples and barely nothing else. Not having much of a choice, I grabbed (you guessed it) an apple and posed the stupidest question I’d ever before or ever since asked: “Are the apples good to eat?”

“Unless you like them in spring when they’re really ripe on the vine!” came a reply from the other room.

November marks the start of orange season in Florida

Boy did I feel dumb. The consolation prize was the apple was as good as it looked and sounded. Just a big old crunch on that first bite. It was October in Dutchess County, New York. Of course the apples were good! What part of fall didn’t I understand?

How To: Detect a Cold Front
Fine art of forecasting good weather

We’re still waiting for our first official cold front …

But no reason to get worried quite yet.

This histogram shows the frequency that the first official cold front (i.e. two consecutive nightly lows below 60° F) arrives to Naples Florida, as based on the historical record from 1941 to present.

By “official” cold front, I’m going by Morton D. Winsberg’s definition in his seminal book Florida Weather. It’s a book that I’ve read over and over again. I call it a rereadable. Keep in mind Winsberg’s definition doesn’t count just drier air, an end to the summer rains or slightly cooler morning and evening temperatures. For the cold front to be “official” it needs to be a true blue slug of continental air that sends nighttime lows plunging under 60° F for two days in a row. Or in other words, it will inspire you to wear long sleeves, if not a scarf. And yes, if you’re a year-rounder who’s endured a full summer, it will have you celebrating, too.

As for when they arrive, it varies from year to year. Some years we get what I call an abnormally early teaser front (i.e. 2000) in early October, but most years (as shown by the distribution curve above) our first real dose of cold air doesn’t arrive until a week or two on either side of Halloween. Then there’s the year’s we have to wallow all the way to the end of November to get our official dose (i.e. 2013, 2020).

Thus my prediction: I’m going to be conservative and say by Thanksgiving it will have arrived (unless it’s another 1986 – see chart above).

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Best fall foliage?
Beauty is in the eye of the beholder

Fall foliage normally doesn’t come to mind in Florida, but should the annual shedding of the cypress in Big Cypress Nat’l Preserve actually rank first (even over New England)?

This unbiased opinion piece says “yes.”

Discover why at Go Hydrology


In other Go Hydrology news:

  • Find out about a new concept called “Almost Big Rain Days (ABRDs)” and how its revolutionizing our understanding of how rain falls.

And as always, thanks for stopping by!

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