Green means light wind, like today. Mainly for greenhorns and visiting parents, but it is possible to spice things up with creative use of equipment in ways it wasn't designed to be used.
Green/yellow: The wind is light but with storms in the area, so there's at least a chance of fun should one pop up.
Blue: The flag experienced sailors want to see every day. Unfortunately, we only see it about once a week at this latitude, even less in August. Heavy rating required (wind averaging >17 mph or unusually gusty).
Blue/Yellow: Blue with storms in the area, and it's probably warm and humid out too. Arrgh.
Blue/Red: For experienced windsurfers--wind is averaging >25 mph. Keelboaters should also look forward to blue/red, but for some reason, most don't. Maybe we're awarding skipper ratings too easily..?
Red: No sailing. unless you're clever (mainly applies to kboats). Always keep an eye on the radar, and if it's green/yellow or blue/yellow, position yourself on the far side of the lake and stay there. Then if a storm comes, you'll have to sail back! In so doing, you'll gain valuable experience (if you survive). This trick has been used in the past, although we're not sure it was actually done intentionally.
Purple: In days past, the practice flag meant beginners with no ratings could safely go for a float.
Finally: there is a secret color that means anything goes.
An example of "blue/yellow" conditions would be today's forecast for Honolulu: partly cloudy, 89 deg, wind NE 15 gusting to 23.
We had a day like that here once. I think.... back in 1999....
