Marathon (Sombrero) seaweed today

SEAWEED RIGHT NOW

High

Latest report: very heavy sargassum.

Piles on the sand, mats through the water, and a strong rotten-egg smell. If seaweed ruins a beach day for you, pick another beach today.

No red tide effects expected.

Updated Jun 15

See Marathon (Sombrero)'s full ShoreScore and best window →

What this means on the sand

Sargassum is a floating brown seaweed that drifts ashore from the Atlantic in pulses, heaviest from roughly May through August. Light levels mean scattered clumps you can walk around; heavy levels mean thick mats along the waterline, a sulfur smell as it breaks down, and tougher entry into the water.

ShoreScore folds this reading into Marathon (Sombrero)'s overall 0-100 score alongside live weather, surf, UV, and official water-quality testing, so one number tells you whether it's worth the trip.

Seaweed at nearby beaches

Coco Plum Beach (Marathon) · Bahia Honda Sandspur · Bahia Honda · Islamorada (Anne’s Beach) · Harry Harris Park (Key Largo South) · All beaches

Also for Marathon (Sombrero): today's water quality and bacteria test →

Source: NOAA, refreshed daily. Informational only, not for safety decisions.