Well, that's a relative question.
To a Seattle or New Orleans, probably nothing they're not used to.
To a Chicago or Atlanta, probably more so than they're used to.
To a Phoenix or Albuquerque, God is angry and has decided to reflood the world.
So far, West Palm Beach has received 30 inches of rain - most of that in the last three months. Expect rain sometime while you are there, generally in the afternoon, probably heavy. West Palm is close enough to the Atlantic where you'll get sea breeze that keeps most of the storms away, so when it does start raining, it's pretty heavy.
Except it to be hot and humid regardless of whether the sun is out.