Hi,
One point I would like to make is the sea conditions can have just as much of an effect on your sailing as the wind speed. Where are you sailing? A small lake will be a lot different than open water where bigger waves can develop. Also, which way are you going? If you are just out for day sail, then it doesn't matter but if you have a destination, beating upwind for a few hours will not be comfortable, while sailing downwind will be a lot easier.
I sail on the Long Island sound, on the south side. A 20 kt wind from the south is great because the water will be flat (the land prevents big waves from forming). Last night I went racing. The wind has been from the east at 15 kts for two days. The sound is very long to the east and 3-4 ft waves developed. Going upwind was 'interesting' The apparent wind was 20 kts, the boat was heeled 25 degrees (even with 5 people on the rail and the #2 headsail) and we pounded through the waves with a wet ride. When we reached the windward mark and and headed downwind, it was like a different world. The apparent wind dropped to about 10 knots, and the waves made it fun as we surfed down them.
If you haven't tried it, I suggest you put a reef in the main, roll up the headsail 20% or so (the max most roller reefing headsails can tolerate and still have any sort of shape), and go for it. Try to start on a beam reach. This will be fast and should not heel too much. If that
seems ok try beating upwind. After beating for some time turn and run downwind home and enjoy the ride!
I like fall sailing because there is usually a lot more wind. I take my 150 genoa down and put up my 100
jib.
Good luck,
Barry