How much rain will kill a marijuana plant in a bucket?

It takes a fair bit of rain, Considerably days, It also depends on how old your seedling is, aka first few weeks yes it can definitely It's not so much the rain as much as it is the constant pounding on the plant, If it's mid way through maturity I wouldn't worry so much unless it's pouring 24/7 than I'd recommend bringing it indoors, Young seedlings aka a few weeks into sprouting might stress and die if they are over watered/dealt with constant pounding of rain!