There was rain forecast for every day I was there. A few days before I left, it was supposed to rain something like 5 inches last Thursday, but then that forecast got changed to less than half an inch, then nothing by the time I left. It only rained twice: Friday evening it sprinkled a bit, and Saturday night it stormed pretty hard for a few minutes, then rained on and off for about an hour or two. Either way, rain won't affect your diving unless it's a really bad storm and the port gets closed due to dangerous conditions, usually because of a strong north or southeast wind.
That said, the National Hurricane Center is tracking a potential TD right now.
Atlantic 5-Day Graphical Tropical Weather Outlook There is a 20% chance of it developing into a storm in the next 5 days. But even if it does, it looks like it will be beyond Cozumel by the time you get there.
Even a TD or TS is no worse than a summer thunderstorm up in the mid-west for example - I've been through much WORSE TS's in Minnesota than any TD or TS I've experienced here - people tend to "freak" because the word "tropical" is in front of it - that is only a GEOGRAPHIC term! Take the word "tropic" away and you have "depression" = weather disturbance and "storm" - a stronger weather disturbance which MOST of the time produces heavy rains and winds around the center of the storm
We would all be SOOOO rich if we had a dollar for every opportunity we have to answer the "the forecast says it's going to rain every day of my trip" post - hahaha!
Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Tue Jun 12 2018
For the North Atlantic...Caribbean Sea and the Gulf of Mexico:
1. A large area of showers and thunderstorms located over the western
Caribbean Sea just to the east of Nicaragua and northeastern
Honduras is associated with a sharp surface trough. This area of
disturbed weather is forecast to move westward to northwestward over
Central America and the Yucatan Peninsula during t
he next couple of
days, and little development is expected during that time due to
strong upper-level winds. However, environmental conditions could
become slightly more conducive for some development when the system
moves into the southwestern Gulf of Mexico by the end of the week.
Regardless of development, this disturbance will likely produce
locally heavy rainfall across portions of Nicaragua, Honduras,
Belize, Guatemala, and the Yucatan Peninsula through Thursday.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...20 percent.