Do Naples exteriors need more care than homes up north?

Before naming what differs, it is worth saying plainly what does not: the organism behind roof discoloration is not a Florida organism.

GAF's current bulletin on shingled roofs says it in one line: “Blue-green algae grows across the U.S. and Canada.” ARMA writes that algae discoloration of roofs “is most widespread in the Gulf States and along the Northwest and Eastern Seaboards,” and adds that it is not confined to those regions.

Florida is a Gulf State, but neither document calls the algae a Florida problem or gives a northern rate to compare. Whether algae grows faster in Naples than up north is its own answer.

The first difference is a reading of NOAA's table, not a growth rate.

In NOAA NCEI's 1991 to 2020 monthly normals for Naples Municipal Airport, the coolest month is January, averaging 65.3 F, and the warmest is August, averaging 83.3 F. A normal is NOAA's conventional 30-year average, and NCEI marks these values “representative,” its flag for a station with at least 10 years of valid observations, with missing months estimated from surrounding stations.

No northern station was read for this answer, so up north gets no number here, and no source read publishes a temperature that algae needs. All twelve months at Naples Municipal Airport are laid out on the seasons page.

NWS Miami divides its part of Florida into two seasons, and one window makers' guide writes a separate instruction for the coast.

NWS Miami writes that southeast Florida has two predominant seasons, summer and winter, and that autumn and spring “are included in the winter season because these two transition periods are drier and cooler than the summer season.” That study rests on Miami International Airport records, so it describes the region, not a Naples station.

The PGT, CGI and WinDoor care guide sets a monthly cleaning line for owners in a coastal area against a yearly line for everyone else, and adds that environmental factors may call for more. That is the makers' instruction for their own windows and doors, not a service schedule, and it is the one coastal against inland comparison in the sources read; the frames and cadence section of the window cleaning page quotes it beside NGA's line.

The same guide names salt spray deposits on aluminum frames. What salt air does to each material is on the salt air answer.

The last two differences come from UF/IFAS, and neither is about algae.

UF/IFAS describes two short lovebug flights a year across Florida, one in April and May and one in August and September.

On pollen, UF/IFAS writes that Florida has more frequent and longer pollen seasons than most of the United States, that Florida trees often release pollen “from January to June,” and that February to May is peak pollinating season for the state's 11 oak species. The glossary defines love bugs and the pollen season on their own pages.

Every difference above is a Naples or Florida line; none is measured against a named northern place.

No northern station, northern pollen calendar or northern cleaning line was read for this answer, so nothing here says how much more often anything is cleaned in Naples, or how much faster anything grows. TRI Alliance's tile guide puts the general point in its own terms: “Many climates are conducive to mildew, algae and moss growth.” It names no region.

Why the growth shows up at all has its own answers: why everything in Naples grows mildew sorts out the organisms, and whether Naples humidity is why exteriors get dirty covers dew and moisture.