Telltales on your jib
Jack's right. We had a C22 for a handful of years and a C25 for 13 before we bought this boat in '98. Neither the C22 or C25 had anything, although the C25 might have had a windex. I never looked up, I looked at the telltales on the jib. The C34 has a wind instrument with direction and speed. I never use the direction, and only check the speed to confirm what I "feel" and am usually close, but more often I'm right on.
Wind direction is something you have to learn. It takes some time, but there are handy guides, like seagulls and waves and the back of your neck.
Cassette tapes of foreign music are a good start, but once you learn telltales and wind direction, you can take 'em off.
Better yet, buy Don Guillette's excellent Sail Trim Book, available right here on this website.
It is the BEST sail trim book ever written.