Water Cycle

The water cycle is an underutilized yet powerful gateway and passport for getting in touch with nature. | Florida’s cycle Weather | Wet season | Dry season | Endless summer | Waiting for fall | Coolish winter | Spring drought | Hydrologic holidays

Intro - Florida's Flawed Seasons

And How the Water Cycle Simplified the Math

By Robert V. Sobczak

Why chose the water cycle ...

Over the seasons for tracking the year?


Florida has two meteorological seasons: a wet and a dry

Don't get me wrong: The four seasons are great. And let's also not forget, officially they are celestially defined by the position of the earth's tilt as it rotates around the sun even. That being said, we tend to think of them meteorologically the most, or in other words, in terms of the weather.

That's where the seasons and the calendar year for that matter fail us in Florida. For one, the meteorological seasons are skewed quite significantly from the normal continental norms. Summer-like weather lasts for six months, not three. And when fall weather will arrive is anyone's guess. As for winter the season, it's more accurately defined by a spattering of days. And spring? I'm not really sure other than the air is drier but it can get quite hot.

swamp cross section
Swamp's cycle of flood and drought

Using January as the start of the year in Florida is also a complete fail. (Talk about getting the New Year off on the wrong start!) Why? January is smack dab in the middle of Florida's dry season. How can we start a new year when the season still has another 4-5 months on the books? That's where the water year comes in handy. It starts in May when the water table bottoms out and the wet season is about to begin.

So the big solution calls for a two-pronged approach: We replace the water cycle with the seasons and aligning our new annual clock with May, not January, as the start of the new year. And here's the twist: we don't have to drop the seasons and calendar year completely. We keep them in the mix, too. It's not about replacing the old regime completely, it's about custom crafting it to fit into Florida's unique meteorologic mold.

The water year, wet season and dry season help us simplify the seasonal math.

Recent Blog Posts

New “water year” approaches
Why water year trumps calendar year

The start of May marks the beginning …

Of a new water year.

Why May?  Here’s the reasons:

  • In south Florida that’s when water levels are normally at their low point.
  • May through October 31st is the rainy half of the year
  • Summer showers usually start in May.
  • To confuse everyone.

Actually, using the water year helps simplify the math. The six month summer span (May-Oct) marks our reliably rainy half of the year whereas the six month winter span (Nov-Apr) marks the time when rains are the exception, not the rule.  October and May are actually “shoulder season” months  They can go either way — wet or dry, and sometimes both. But in terms of hydro bookkeeping, organizing the water year by equal 6-month wet and 6-month dry seasons avoids having the start the year in the middle of the dry season (January) and ending the year on two orphaned months (November and December) of the following water year.

Water Year Time Piece

One more point of confusion:

Some people say we’re entering the 2022 (i.e. not the 2023) water year.  While on the one hand, that sort of makes intuitive sense, for the reason that the bulk of the coming water year both in terms of months (8 of the 12) and rainfall (43 inches of the 55 inch annual total), the convention is to number the water year according to the calendar year it ended. And if you think about it, that does make sense: This year’s graduates will be “Class of 2022,” not 2021.

Nobody said the water cycle was always easy, but using the water year definitely helps us simplify the hydrologic math, and puts us in tune with the water cycle in a way that the calendar year falls short.

Water calendar revolt
And how it simplifies the water cycle

As if the switch to Daylight Savings …

Wasn’t already confusing enough:

Firelight Radio is available on Apple Podcasts and Podbean

Here we are not even halfway into the calendar year and we’re already leaving 2021 behind?

The water year starts anew May 1st

The good news:

Doing so greatly simplifies the hydrologic math.

Life is better around the campfire

This podcast from Firelight Radio explores the topic in greater depth.

Read more

Dual Calendar?
Julian vs Water Year

A year older, a year wetter

Normal people turn the calendar to a new year on January 1st. Not hydrologists — not even close. And rightly so. January falls in the middle of south Florida’s winter dry season. Starting the year anew in January splits the dry season in half — a big no-no if you’re trying to tabulate dry season rainfall and full year water amounts. The solution? Enter the water year. Up north on the continent the water year starts on October 1st (long story). The short story is that south Florida’s water starts anew May 1st each year on May 1st. Don’t expect a big parade or a big summer storms to magically start on cue on the first of the month. And to be certain, the first few weeks of May are usually dry. But make no mistake: It’s also the month that the humidity hammer drops and summer rain clouds start to emerge, even if it’s sporadic at first and usually doesn’t start in earnest towards the latter Memorial Day half.

The upside, and why hydrologists like me are adamant on this point: Starting the water year on May 1st allows us to split the year into two equal 6-month wet and dry seasons.

animation switch

Start of wet season?

There’s a tried and true meteorologic saying that “all droughts end in flood.” The caveat in south Florida is that drought-ending rains occur every year. It’s called the start of the wet season. While the rains often take a good couple weeks to flood water back everywhere in the swamp, the meteorologic shift from rainless skies to regular afternoon rains can happen quickly like a flip of a switch.

Can you guess the day whereabout it usually starts? Hint: It’s a holiday.

a. Fourth of July – 7/4

b. Memorial Day – 5/30

c. Tax Day – 4/15

e. Mother’s Day – 5/8

f. Father’s Day – 6/19

Cornbread model
And how it helps us describe drought

When people hear “swamp,”

They usually think water (and alligators).

But you can’t talk about the Big Cypress Swamp, or anywhere in south Florida for that matter, without mentioning its winter dry season, and specifically the “spring half” when the water table drops to its annual low. As much as we’ve tried, it’s hard to get the point across. And the thing about drought: It’s just not a single number, or framework for quantifying it. That’s where the diagram above come in handy. It both differentiates among (1) meteorologic, (2) swamp flooding and (3) soil moisture metrics for measuring drought — and also puts them into easy to understand corn chip and cornbread equivalent scales. Currently we are heading toward the deepest part of the spring drought season, but not there yet (see the dotted line).