Yes, I'd like to know this too. We're there May 19-23, and the weather forecast currently shows rain everyday. Are these just short rain showers, or are we potentially looking at being "rained in" every day?
The weather in May GENERALLY seems to be pretty good. However, a good bit of rain is certainly not out of the realm of possibility. We've seen sunny skies all week....and we've seen rain for a good part of the week. It's very possible that you'll see a few afternoon thunderstorms, at a minimum....kinda like summertime in many parts of the US. It seems that they tend to form up over the mountains inland, and migrate out over the coastline.
You never really know what you're going to get until you arrive.