June in Naples

Normal rainfall at Naples Municipal Airport rises from May's 2.76 inches to June's 7.41 in NCEI's 1991 to 2020 normals, a rise of 4.65 inches and about 2.7 times May's total, the largest rise between two adjacent months anywhere in the twelve-month table; the only larger change in either direction is the fall from September's 8.60 inches to October's 3.93, and May in Naples reads the month on the near side of the rise. The provisional count of days with at least 0.01 inch of rain rises the same way, from 7.9 in May to 14.7 in June, about 1.9 times.

By the daily normals, about 44 percent of June's rain, 3.29 of 7.41 inches, has already fallen by June 15. Every figure is a climate normal for the airport, a thirty-year average, never a forecast of how wet a single June turns out.

In NCEI's 1991 to 2020 daily normals, Naples Municipal Airport's normal high reaches 90.0 F for the first time on June 17 and does not read below it again until September 11. The daily chance of at least 0.01 inch of measurable rain first reaches 50 percent on June 24 (50.1 percent, provisional) and holds at or above that mark through August 31, both readings of a smoothed thirty-year average rather than a date on which any single June actually turns.

NWS Tampa Bay writes that in most years the thunderstorm season across its own West Central and Southwest Florida area sets in during the “second or third week of June,” once its listed ingredients come together, among them a Bermuda High, Gulf water at 82 to 83 F or warmer and dew points at or above 70 F. The heat that arrives with the season has an answer per surface: roof cleaning in the summer heat, sealing pavers in the summer heat and windows in the summer sun.

The South Florida Water Management District's 2018 report sets its wet season at June through October, seventeen days after the May 15 both weather offices print for their own regions. The National Hurricane Center opens the Atlantic hurricane season on the very date, June 1, running to November 30, and writes that the first named storm typically forms in mid to late June, June 20 in its table of 1991 to 2020 season averages, with a caution that any one season can vary considerably from those dates.

NWS Miami's “stormiest” phase runs mid-May through early July, and the phase NWS Tampa Bay describes for West Central and Southwest Florida, when severe storms are most likely, runs late May through June; each belongs to its own office, and the two three-phase calendars are laid out as a term at rainy season. The storm calendar as a term, with its bookends and its average-season counts, sits at hurricane season, and should a roof be cleaned before hurricane season answers for the roof. Whatever a storm does to a roof or a window frame is for a licensed roofing contractor, the installer or maker of that window, and the insurer to read, not for a month page.

A paver sealer's dry-hours condition is the same in June as in any other month: ICPI's Tech Spec 5 says the cleaned surface “must be completely dry prior to applying most sealers,” with a full 24 hours free of moisture or dampness before the coat; SEK-Surebond's TB.6 asks for the same 24 hours, and Techniseal's two sheets want no rain forecast for the 24 hours after. What June changes is how often a day offers both spans back to back, which this page reads off NCEI's provisional 14.7 rain days and the daily rain chance at or above 50 percent from June 24 on, a statement about frequency and not a maker's rule; sealing pavers during the rainy season weighs the two windows against the season, and what happens if rain hits freshly sealed pavers covers the window missed.

The season's storms bring the National Weather Service's lightning rule, written for people, not surfaces: thunder means lightning is close enough to strike, and shelter holds for at least 30 minutes past the last thunder. The day's lightning danger is NWS Miami's call, described in its Hazardous Weather Outlook on a scale from none to slight, moderate and high, and roof cleaning in the rainy season puts the shelter rule against a roof job. NWS Melbourne's statewide lightning climatology, an average built from 1986 to 1995 flash-density maps, has the flash rates over the peninsula beginning to dominate in June as the east and west coast sea breezes collide, with south Florida a minimum on almost every monthly map.

The season's own moisture arrives with it. NWS Tampa Bay writes that the season is typically accompanied by persistent dew points above 70 F, NWS Miami's wet-season definition has almost daily surface dew points in the 70s, and GAF's TAB-R-102 says of blue-green algae that “Dew is the primary moisture source.” Setting those three lines side by side is this page's reasoning: none of the three measures growth, and why algae grows faster in Naples than up north is where the rate question lives.