El Nino Watch
Turn what a beach or pier cam shows into a rough wind / wave estimate before a ferry.
Ocean
A way to turn what you see on a coastal camera into a rough wind / wave estimate, using the Beaufort scale sailors have used for 200 years.
Limits.
Look at open water, not the shore break, and watch for 30-60 seconds: - Calm to light (Beaufort 0-2, < 7 knots): glassy or small ripples, no white. Ferries run normally. - Gentle to moderate (Bft 3-4, 7-16 kt, waves ~0.5-1 m): a few scattered whitecaps. Normal crossing, some spray on speedboats. - Fresh (Bft 5, 17-21 kt, ~2 m): many whitecaps everywhere, some spray. Speedboats and small boats may be cancelled; big car ferries usually run but it is rough. - Strong (Bft 6-7, 22-33 kt, 3-4 m): large waves with white foam crests, foam blown in streaks, spray. Expect cancellations; do not take a small boat. - Gale (Bft 8+): sea heaps up, long foam streaks. Boats stay in port. Also check: rain curtains (grey vertical streaks) moving toward the camera = a squall arriving in minutes; a hazy, milky horizon = poor visibility.
Which cams: north coast (Fisherman's Village, Big Buddha / Bangrak) for the Samui to Phangan / Tao crossing; Bang Po (north-west) for the Nathon / Donsak lane; Koh Tao Mae Haad for the far end; east coast (Crystal Bay, Lamai) for NE-monsoon swell.
Leaving the island means a boat or a Bangkok Airways flight. From about October to December the north-east monsoon brings wind and waves to the Gulf of Thailand; the Thai Meteorological Department then advises small boats to stay ashore when waves reach 2-3 m. El Nino changes how wet and stormy that season is.