In a light afternoon rain, everyone flocks to the hottub.
We've not been there during a deluge or when there is lightening, so I don't know if they shut the hottub down or what.
But after 12 trips, we've never been there where it rained for more than an hour. The biggest problem is that it seems to get the sheets on the rooftop jacuzzi beds wet, and the staff pulls up all the sheets and don't replace them later around midnight when they are needed most.
Weather never seems to be a problem at Desire.