if you do a search you'll find some threads on this subject. (look in road biking/touring as well as commuting). In a nutshell, hopefully, most people are aware that the "rubber tires" theory of "insulation" is a myth. Unless you're on a carbon fiber bike you're pretty much riding around on what amounts to sitting in a steel folding chair or an aluminum lawn chair in a lightning storm- not really the best of ideas.

If you are in big city, like NYC, and riding on narrow streets between big buildings you're less likely to get struck than if you are riding along the river on an open stretch of bike path. Granted the chance of getting struck in almost any case is pretty small but reducing the odds is not a bad idea. States like Florida, that get a lot of storms, and have a lot of open flat space have a higher incidence of lightning strikes of people. Perhaps the greater risks to cyclists during thunderstorms come from reduced visibility for both the cyclist and motorists, blowing debris, falling trees and branches and flash flooding. Add all that to lightning and it's probably a good idea in most cases to take shelter when a thunderstorm passes. I think people who continue to ride in a bad storm tend to do so either out of ignorance, machismo, willingness to risk and gamble or are in such a hurry they just don't give a crap about getting struck by lightning.

For me today was a great weather day. Pretty much not a cloud in the sky and temperature in the mid 70's. I stopped at the par-course fitness area along the bike path and did a little workout- never did that before- that was cool.