Cancun, Mexico has beautiful weather year round so there really isn't a bad time to vacation in Cancun. The very best weather is between February and April, during the spring, which is also high season so you will be paying more for accommodation.

The Cancun water temperature is pretty consistent year round, hovering between 75° F (24° C) and 85° F (29° C). During the winter months the water is about 75° F (24° C) and 80° F (26° C). Summer months, the water temperature gets up to 85° F (29° C).

The water reaches its warmest temperature in late August, when it can feel like you're swimming in a bathtub. However, even during the coolest period the water is still great for swimming.