Can windows be cleaned before hurricane shutters go up?

A hurricane shutter or storm panel does one job: it covers the outside of the glass. It does not wash it, wipe it or change anything already on it.

Whatever film, dust or residue sits on a pane the day a panel goes up is still sitting there the day the panel comes back down, because nothing about a covered window removes anything from it. The outside of the glass can be reached before a panel goes up and after it comes down, not while it is covered.

No maker or association document read for this page talks about cleaning glass before shutters go up, and that gap is worth naming rather than papering over.

What NGA does publish is a general rule that holds whether shutters are coming or not: dirt and residue are not to stay on glass for an extended period of time, and water or cleaning residue is not to stay on the glass or adjacent materials, in the words of its quick-reference list. Neither line is written about shutters. Reasoned from NGA's rule, though, a panel adds to the time dirt and residue stay on a pane rather than taking any away. What is already on the glass at that point, including any salt film that has not been addressed, is the state it stays in until the panel comes off. Shutter installation, panels and tracks are a shutter contractor's work, not a cleaning question, and whether a roof should be cleaned on the same timeline is answered separately at should a roof be cleaned before hurricane season.

The National Hurricane Center's own calendar sets the frame this page uses, and it is a span of months, not a clock running toward one storm.

The National Hurricane Center dates the Atlantic hurricane season from June 1 to November 30, with its peak on September 10 and most activity from mid-August to mid-October. That calendar is set out, alongside Naples' own rain and temperature normals, on the storm calendar. Nothing here is a reason to rush a cleaning ahead of a particular storm. The point is only the mechanism: a pane that goes behind a panel keeps what was on it, whenever in the season that happens. What a storm's own wind and rain leave on glass afterward is a separate question, answered at why windows are spotty after a storm.