And well he should be. Weather, as we all know, varies considerably from one location to another. Local effects such as islands, straits, narrow passageways, hills, etc., disrupt the wind flow, even causing it to blow contrary to the direction it should be blowing, which is from high pressure to low pressure. To get an accurate picture of the wind flow, an anemometer would have to be placed at locations less than one mile apart. We know that is not feasible, so what one must do is take a report from a reliable location and apply that report into areas nearby.
Experience plays a major part.
Even though the wind may be different at some other location, given the same meteorological situation, there should be some correlation. Let s say you start out from Marina A with a certain wind speed and direction. If the meteorological situation is not changing rapidly, what you encounter at Point B should be what you encounted on a previous trip, given the same conditions. So the report from the marina where you started is vital to having a safe boating trip. That s why most marinas employ the use of reliable weather systems such as the Capricorn.