The wet season runs from about July/August to Oct in the southern elements of the region. This is the hurricane time also. It’s also steaming incredibly hot! Holbox is really a hotspot for swimming with whale sharks (see range 4 on this checklist). It’s also perfect for snorkelling, looking at https://edwinxxlvd.dm-blog.com/28840318/getting-my-mexico-tourist-attractions-to-work