Check wind and weather for sailing.
Sailing decisions follow the gusts rather than the average wind, because the gust is what loads the rig. The Beaufort scale converts wind speed into the standard force bands used in forecasts, the gust factor shows how squally the air is, and wave height relative to boat length is the seaworthiness measure that matters: waves above roughly a fifth of hull length become genuinely difficult for a small boat.
Beaufort force and sea state
Beaufort force from standard wind speed bands in knots; gust factor = gust / steady wind; wave to length ratio = wave height / boat length
Conditions at sea change quickly and this is not a substitute for an official marine forecast, local knowledge or your own judgement. Decisions about going to sea rest with the skipper.
Reef for the gusts, not the average, and reef early — the common rule is that if you are wondering whether to reef, it is time. Force 5 gusts usually mean the first reef in a small cruiser.
As a rough guide, waves above about a fifth of hull length become hard work and above a quarter become dangerous, particularly when steep and breaking.
A gust factor above about 1.4 indicates unstable, squally air where sudden increases in load are likely. Steady wind of the same speed is far more manageable.