It depends on the rain. Our first visit to CC was bright and sunny. The next one was overcast, cloudy, and drizzle. People continued doing their normal beach activities, but they would not let anyone raise the beach umbrellas.
But this year in July, the storm that hit was so violent that they cleared the beaches. MANDATORY. (HEAVY rain, lightning, wind). It POURED for at least 1.5 hours. Most people cleared out and headed back to the ship soaking wet. We took cover in the bathroom (DW, DS13, adn DD8) and waited it out, then returned to a deserted beach for the last 2 hours of our CC stay.