The Beaufort Winds scale works for me.
get your copy at www.r-p-r.co.uk/beaufort.html
Most 100% sailplans are good to Force 4, a few work well depending on point of sail and hull design to Force 5.
If you can remember that scattered whitecaps are fun and solid whitecaps mean reduce your sailplan, that''s a good start.
May you never be in force 9.