temperature check

Summer’s final stretch
And why fall isn't here yet

Celestial fall officially started …

on September 21st.

Comparison of night and day time temperatures in Naples, Florida to farther “Up North”

But in south Florida,

it’s still a waiting game before autumn starts to kick in.

Daytime highs are still in the high 80s and night time lows are still above 70 degrees.

According the book Florida Winter, fall in Florida officially commences with the onset on two consecutive nights that drop below 60 degrees. The animated map below shows that typically happens around the fourth month of November for south Florida.

Animation of when fall “typically” arrives to the Florida peninsula

If that seems like a long wait,

Not to worry: Fall doesn’t happen in one fell swoop.

We get plenty of signs along the way.


Signs of fall
Fall arrives in many ways, just not temperatures

Signs of fall in the swamp are subtle,

But they are there if you know where to look.

Early October:
Resurrection fern shrinks
to shriveled state indicating
less rain
Late October:
Dwarf cypress prairie
become needle bare indicating
less daylight hours
Early November:
Cold water seeps into boots
indicating lower air temperatures
Late November:
The cypress-pine
swamp mosaic really
starts to “pop”

Can you think of others?

Thanksgiving plunge?

Thanksgiving was a bit of a …

Pivot point for air temperatures in Naples, Florida.

The above charts use the 7-day running average

Nighttime temperatures have dropped about 20 degrees.

Not enough for long pants, but a scarf and hat were needed for a couple evening walks.


Real fall is out there

In south Florida,

We could feel it, if not see it (in the data).

Comparison of continental
and penisular air temperature trends 

Compare that to up north …
Where the fall dip in air temperature is unmistakeable.
That includes Florida’s own Tallahassee (dotted green line) which is more continental than peninsular.
swamp dictionary

True Florida Fall
Not to be confused with the calendar version

I know everyone’s excited about cold air about to move in.

But let’s put it in perspective, too.

Red bars indicated the five-day
forecast for Naples, Florida

Yes, it will be cooler (and delightfully crisp).

However, it will not meet the criteria for “official” Florida Fall.  For that to happen, nighttime low temperatures need to drop below 60° F for two consecutive nights in a row (source: Winsberg’s Florida Weather).  That’s when fall in Florida begins.

Nor will it meet the standard for an “official” Florida Winter Day.

For that to happen, daytime temperatures have to stay at 70° F or below.

Nonetheless, I’ll take the cool air!

Fall is delayed (until further notice)

South Floridians wait in eager anticipation …

For the first front of cool continental air to arrive.

Chart showing the frequency distribution
of when the first “official” cold front arrives
in Naples FL, by decade

The problem as of late:

Starting in the 2010s, the arrival of the first official cold front has slipped from October to November.  Or in other words, it’s happening later than normal.  The good news is a front of cooler air is finally on its way.  The bad news is that it will not count as an “official” front.

For that to happen, nighttime temperatures have to drop into the 50s for two consecutive nights.

Very ripe on the vine

Just as the arrival of apples ushers in fall up north,

Oranges are Florida’s tell-tale sign that winter has begun.

One month ago: all apples

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 – the few drops they did have were more precious because of it. Also conspicuously absent were “seasons.” The natives always scoff indignantly. “Of course we have seasons!” they’d sternly rebut …

Followed by a subtle litany explained in condescending overtones.

Up on the continent in late fall

Regardless, I found myself routinely pausing in thought during my entire stay in Arizona trying to remember what month it was; “Is it April or August?”

“Oh that’s right, how could I forget – it’s January!”

In any event, I arrived at my brothers doorstep after a five-hour drive from Cape Cod, not so much in a state of “time out of mind” as I was a “mind out of season.” Opening his fridge, I was shocked to see apples packed everywhere – up on the egg racks, behind the butter, in every unused drawer.

I grabbed one instinctively and proceeded to wash it under the faucet.

“Is it alright if I eat an apple,” I asked.

“They’re pretty good,” a voice deadpanned from the other room, “unless you want to wait until spring for them to get really ripe on the vine!”

Today: Move over apples!

Confused, a bit embarrassed, but hungry – I ate that apple. Thinking about it days later I broke out into riotous laughter (and for a few years running it became a standard joke between my brother and I): Of course the apples were “alright to eat” – it was October, in Dutchess County, orchards everywhere:

“What part of fall didn’t I understand?”