Can exterior cleaning wait until after the rainy season?

NWS Tampa Bay dates the rainy season for Southwest Florida from May 15 to October 15, and describes it in three stretches rather than one block.

The office writes that the rainy season “usually has three phases”: late May through June, “the period when severe storms are most likely”; July through early September, “when the rainy season peaks”; and mid-September through early October, the “wind down” phase, which “tends to have higher rainfall variability due to potential tropical systems and early-fall cold fronts.” NWS Tampa Bay adds that “similar to hurricane season, the rainy season may occur before or after the aforementioned dates,” and that its beginning “is usually a transition period rather than a single date.”

A wait aimed at the end of the rainy season is aimed at a date the office itself says may move. The rainy season has its own glossary entry.

Two places a season-based rule could live, the county's water ordinance and the roofing trade's own method, do not put one there.

The county's washing rule, Collier County Ordinance 2015-27 as the 311 knowledge base publishes it, sets equipment and drainage conditions but names no season; the water calendar on the seasons page quotes the rule with its drainage condition.

ARMA's asphalt-shingle procedure attaches no season either. ARMA does write that treated algae will disappear and wash away with subsequent rains, but that line follows its own rinse step, names no month and is no reason to time a cleaning to the rain. Whether a roof can be cleaned in the rainy season is its own answer.

The one place a wait changes a published condition is paver sealing, because sealing turns on a dry surface, not on the calendar.

ICPI's Tech Spec 5 wants a dry surface and 24 hours without moisture before most sealers, and SEK-Surebond's TB17 wants roughly a dry day on each side of the application, with its own exception for select sealers. Neither names a month, and both documents are quoted in full under the sealer's wait when all three exterior cleanings share one visit.

The Naples Municipal Airport rainfall normals put the heaviest months inside the rainy season and the lightest from November through February. Those are monthly averages, not a count of dry days, so they make a dry window harder or easier to find without promising one. Sealing in the wet months is answered at can pavers be sealed in the rainy season.

A roof cleaning carries no such published dry-window condition: ARMA's and GAF's shingle procedures describe a dwell and a low-pressure rinse, with no wait for a dry stretch. What the wet months leave on a house in the meantime is covered at what the summer leaves on a seasonal home, and which month suits the whole exterior at the right month for exterior cleaning.

A wait timed to the rainy season is not a wait timed to the storm calendar, because the two do not end together.

The National Hurricane Center writes that the Atlantic hurricane season “runs from June 1 to November 30,” that tropical cyclone activity sometimes occurs before and after those dates, and that the season peaks on September 10, with most activity between mid-August and mid-October. NHC's end date falls about six weeks after NWS Tampa Bay's October 15 rainy-season date.

September's rain and storm overlap covers the month where the two calendars meet, and the glossary defines hurricane season and the dry season on their own pages.