I have found above 22.5 knots that the average is a little higher than expected, but the gusts are usually a little lower than expected.

In general they tend to over read under 22.5 knots

be careful reading them because looking at the max and avg does not tell you everything you need to know, especially what the min wind was. On a gusty day check out the airport v DesalCentral (aka Kurnell) to see what I mean.

Also some of them read funny in certain wind directions because of where they are.

In summary - there is no better way than to stand on the beach with sand blowing up to your hips (or knees in my case) and say "I think it's windy..."