We had pretty rubbish weather in Mexico last month, but I didn't let it spoil my vacation - but then again the room we had, the facilities the hotel had, meant it was still pleasant (ie there was a huge spa to use in the rain, we had a 2 room suite and partially covered balcony, so I could sit in a jacuzzi outside and read while the rain poured down around me, or order room service and eat at a table (as opposed to awkwardly on a bed as you sometimes have to in smaller hotel rooms). Had I been in a small room, with nothing to do when it rained other than go stir crazy, yup, I may have a different outlook - plan for the worst, hope for the best!