vtjim, don't get me wrong--if it was just rain (even a lot) I would have been out there! Got the jacket, fenders, and disk brakes. It's the close lighting (>1 mile) that scares my wife. And since she encouraged me to buy a new bike who am I to argue? Here is the list:

Conditions I would not ride my bicycle in:
Thunderstorm in the immediate area (hear thunder closely)
Line of thunderstorm or strong storm coming toward us (by radar)
Hurricane (NOAA high wind warning/heavy rain warning)(we do get these in Atlanta, about once or twice a year)
Freezing rain (crazy drivers skating on the road)
Sleet (tried that once-the facial sting was bit much)
Hail (probably would be a major thunderstorm anyway)
Fog at the house so thick you can't see past the neighbor's house (never has happened)

Conditions I would ride in, but would take a different route, mostly the bike path:
Heavy fog
Heavy rain
Snow (once a year if that, and if work was open)

Conditions I would ride in, just taking extra care--slower, and allow more time:
Rain
Cold (below 32°F)
Heat (above 100°F)

YMMV