The Mexican Secretary of the Navy reports low levels of sargassum, an algae seaweed that is brown and huge, are low in 4 locations.
This particular seaweed grows in the ocean all over the world, but warm Caribbean waters help it to grow to the point that it can make activities like enjoying the beaches difficult. Hurricane season helps spur the seaweed to shore.
Those 4 areas having almost none of this seaweed are:
Solidaridad (including Playa del Carmen)
In addition these locations have reported only moderate levels of sargassum on their beaches:
Benito Juárez (which includes Cancun)
Othón P. Blanco (which includes Chetumal)