May in Naples

NWS Tampa Bay calls the rainy season's start “usually a transition period rather than a single date,” and adds that, similar to hurricane season, it may occur before or after its own printed dates. NWS Miami, the Naples zone's forecast office, gives the same May 15 start, with a transition it says “can last two weeks or more.”

NWS Miami's date is for the South Florida wet season and NWS Tampa Bay's for the rainy season of its own Southwest Florida area; the dates, the hedges and the season's phases as a term belong to the rainy season entry. The same Miami office's study of Miami International Airport records for 1956 to 1997 finds a median start of May 21 inside a range running from April 16 to June 3, a finding for that airport and those 42 complete years, never a Naples measurement.

The South Florida Water Management District reads the same weeks two ways: its 2018 report still counts May inside a November through May dry season, while its fact sheet starts the wet season in mid-May, and its water year, as that report defines Water Year 2017, opened May 1, 2016. April in Naples sits just before all three of those calendars turn.

NCEI's daily normals split May inside itself. About 1.04 inches of the month's 2.76 inch normal, roughly 38 percent, falls by May 15, and the other 1.72 inches, about 62 percent, falls over May 16 through 31. The daily chance of at least 0.01 inch of rain climbs 17.0 points across the month, and across NCEI's 31 daily values for May that figure never drops from one day to the next.

May's four monthly normals are 2.76 inches of rain, a 78.8 F average, an 87.5 F normal high and a 70.2 F normal low, with NCEI's quartiles of the month's nonzero totals at 1.97, 2.55 and 3.41 inches, and a provisional 7.9 days with at least 0.01 inch of rain and 5.4 with at least 0.10 inch. Every figure is a climate normal, a thirty-year average and not a forecast for how any one May divides.

Naples Municipal Airport's daily normal minimum, in NCEI's 1991 to 2020 series, first reads 70.0 F on May 15 and stays at or above it every day through October 19, dropping back below 70 on October 20. NWS Miami's Miami International Airport study marked each summer season's start on the date the average daily dew point rose above 70 F and stayed there, noting that the daily minimum temperature stayed above 70 F from then on, so the smoothed Naples reading and the published date fall together on May 15. That pairing is this page's reading, a coincidence of an average and a definition rather than a finding either office made about Naples.

The dew point entry defines the term and sets out NWS Miami's use of it as a summer indicator. May's normal high, 87.5 F, also sits above Techniseal's 85 F ceiling for its NS sealer, one more reading of the numbers what temperature is too hot to seal pavers and sealing pavers in Naples summer heat carry forward through the summer.

NWS Miami names mid-May through early July the wet season's “stormiest” phase, when strong and damaging winds, tornadoes, excessive lightning, hail and flooding are most likely. NWS Tampa Bay names late May through June the phase when severe storms are most likely for its West Central and Southwest Florida area, with hail, damaging winds and waterspouts common alongside heavy rain and frequent lightning.

NWS Tampa Bay's climate summary adds that stretches of daily thunderstorms in May are usually tied to an upper-level disturbance or trough rather than daytime heating and the sea breeze alone. Thunder brings the same rule in May as in any month: the National Weather Service's lightning tips treat thunder within earshot as lightning within striking range, and tell you to stay in safe shelter “at least 30 minutes after you hear the last sound of thunder”; roof cleaning in the rainy season sets that rule out for a roof job.

A paver sealer's dry-hours condition does not move with the calendar either: ICPI's Tech Spec 5 says “Allow at least 24 hours without moisture or surface dampness before application” for most sealers, and SEK-Surebond's TB.6 sets the same 24-hour minimum. What changes is how often a month offers that window, and setting May's provisional 7.9 rain days between April's 5.5 and June's 14.7 is this page's comparison of NCEI's counts, not a rule from either document; sealing pavers during the rainy season works the question month by month.

The National Hurricane Center opens its Atlantic hurricane season on June 1 and closes it on November 30, adding in the same breath that tropical cyclone activity “sometimes occurs before and after these dates.” NOAA's Atlantic Oceanographic and Meteorological Laboratory, in its hurricane FAQ, writes that hurricanes have occurred outside the official six-month season, whose dates were chosen to take in over 97 percent of Atlantic tropical cyclone activity, and that tropical cyclones it labels “Out of season” primarily occur in May or December, a line about the Atlantic basin and both ends of the season.

Neither line is a count or a forecast for any one May, and neither is a Naples measurement; the season's bookends, its September 10 peak and its average-season counts belong to the hurricane season entry. Should a roof be cleaned before hurricane season weighs the roof question, and windows before hurricane shutters the glass one. What an early storm leaves on a roof or a window is read by a licensed roofing contractor, the window's maker or installer and the insurer, never off a month's averages.