I've heard of snow grounding planes...

... But rain?? When it's tropical storm rain that is so severe you can't even see through it, yes. Sat on the runway for 2 hours until finally they just closed the airport and sent us home. Where I got soaked walking from the taxi to my front door. Gotta love business travel in this part of the world. At least we never have to wait around for de-icing trucks though.