We are in the tropics so it is generally very warm and sunny all year round with an average daytime high of 25C - 28C ( 75 - 85 F). The winter months are warm and dry - the best time! It rains most in summer but the rain is usually followed quickly by sunny skies.
Tropical rainstorms sometimes occur in the hurricane season which runs from June to October. Tropical rains are spectacular but the island is very porous and the heaviest rains quickly drain off into underground lakes or the sea. Hurricanes normally avoid Barbados and the pattern is reasonably consistent as hurricanes tend to bounce from one land mass to the next and Barbados is somewhat separate from the rest of the Caribbean island chain.