Sargassum Season: Why Cozumel's West Shore Is Not the Riviera Maya

Sargassum seaweed has affected the Mexican Caribbean seasonally for years now, typically building from around April through August and varying enormously from one year to the next. It arrives on open ocean currents, it lands on east-facing shores, and it is unpredictable enough that no forecast published in January is worth much by May.

The geography that matters

Cozumel sits between the mainland and the open water the weed arrives on. The island's developed west shore is leeward — it faces the channel, not the Caribbean — and it consequently receives substantially less sargassum than the east-facing beaches of the Riviera Maya across the water.

That is a real comparative advantage and worth knowing if you are choosing between Cozumel and Playa del Carmen or Tulum in a heavy year. Every beach club, dive dock and hotel beach on this island is on that sheltered side.

It is a tendency rather than a guarantee. A sustained onshore wind can push weed onto the west coast for a few days at a time, and when it does, the clubs rake it.

Where Cozumel's share lands

On the east coast, which is windward, exposed and unraked. In a heavy season the windward beaches can carry a deep seaweed line that sits for weeks. It changes what that coast looks like and not what it is for, because the undertow there means nobody should be swimming anyway.

What it does and does not affect

• Boat trips to Palancar, Columbia and El Cielo are unaffected. Whatever is on the sand is not out at the moorings.
• Diving is unaffected. The reef sits well offshore of anything drifting in.
• Shore snorkelling can be affected at the west-coast entries if weed has come in, because visibility in the first few metres drops.
• Beach club days are the most affected, and the clubs vary enormously in how aggressively they clear.

How to check, properly

Look at recent photographs from the specific beach club you are considering, dated within the last week, rather than at a regional seasonal map. Conditions differ between two clubs a mile apart, and they change within days. Local social media accounts and beach club pages post current pictures for exactly this reason.

If it matters a great deal to your trip, book the reef rather than the sand. Nothing that happens to the shoreline touches the water over Palancar.