Gulf of Thailand Dive Conditions
7-day dive conditions forecast for Sail Rock, Chumphon Pinnacle, and Koh Tao's key sites — for freediving and scuba divers alike. Green means go — scored on wind, waves, swell, ocean currents, satellite visibility and tides. Ensemble-averaged across 4 weather models and calibrated by divers logging what they actually see underwater.
Today's pick Tanote Bay 59 →Last update: Fri 14 Aug, 00:54 UTC · Timezone shown: Asia/Bangkok
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Want to see every metric behind the score? Pick a site above or visit /conditions/sail-rock for the full breakdown (wind + gust + direction, wave, swell, ocean current, SST, rainfall, bloom, tide, model agreement, per-field point contribution).
How the score works
Out of 100, weighted for what matters underwater (freediving + scuba):
- Wind (30pts) — with per-site exposure: sheltered sites get credit when wind blows from the sheltered quarter.
- Waves (20pts) — surface chop, boat-ride comfort.
- Swell (5pts) — long-period groundswell is rare in this enclosed gulf, so it is a light penalty; local wind-chop (counted under Waves) is the real surface driver.
- Ocean current (20pts) — from Open-Meteo Marine ocean currents. Matters for both sports.
- Viz (20pts) — led by satellite Secchi depth (real water clarity), plus 7-day rainfall runoff, wave-stirred bottom sediment at shallow sites, and seasonal turbidity.
- Spring-tide penalty (−0 to −5) — applies only to shallow coastal sites (≤20m).
Forecast is ensemble-averaged across four weather models (GFS, ICON, JMA, GEM). When they disagree by >8 km/h we flag "forecast uncertainty."
Sources & caveats
Data comes from Open-Meteo Marine, a four-model weather ensemble (GFS, ICON, JMA, GEM), and Copernicus satellite water-clarity. Hover a cell for full metrics. Local factors the models can't see — boat traffic at Sail Rock, plankton blooms for whale-shark season, thermocline depth — still matter. Text us on WhatsApp for same-day conditions from the crew.
Why we built this
The most accurate Gulf of Thailand dive forecast — because the existing ones aren't
For years we relied on Windguru, Windy, and local weather apps to decide whether to run our boats. Every one of them is built for sailors — not divers. They tell you the wind speed and the wave height. They don't tell you there's a 0.8 m/s current ripping through Sail Rock that'll make your dive miserable — freediving or scuba. They don't know a plankton bloom just crashed visibility. They don't care about the thermocline at 18m, the spring-tide pull, or whether your specific dive site is sheltered from today's wind.
So we built our own. This tracker blends four weather models (GFS, ICON, JMA, GEM — averaged together), Open-Meteo's ocean data (waves, swell, ocean currents, sea-surface temperature, wave direction and period), real tide predictions from WorldTides FES2022, satellite water-clarity (Secchi depth) from Copernicus Marine as a direct visibility proxy, and atmospheric storm energy (CAPE) for thunderstorm risk. Then we score it for what matters underwater — not generic weather.
The final layer is you. Every instructor and diver who logs a post-dive report — what they actually saw, the real visibility, the real current — calibrates the forecast. Over time, ground-truth beats any algorithm. If you're diving in the Gulf, drop your report. It takes 30 seconds and makes the next boat-load of divers safer.
Who’s calibrating the forecast
Top Divers
- 1 Dominic 6 logs · 3 sites 120
- 2 Diego 2 logs · 1 sites 88
- 3 Carmen Smeets 2 logs · 2 sites 68
Top shop: 100 Degrees East · 120 points
For Website Owners
Embed our live forecast on your site — free
Hotels, dive shops, travel blogs, villa rentals — drop a live Gulf of Thailand dive forecast onto any page in 30 seconds. Always fresh (updated hourly), no setup, no API keys, no account.
- ✓Any of 115 Gulf dive sites, or the 7-day overview
- ✓Mobile-responsive, lazy-loaded (no page-speed hit)
- ✓Works on WordPress, Wix, Squarespace, Webflow, HTML
- ✓Your visitors stay on your site; attribution link back to us
Embedded on your site? Tell us and we'll feature your shop on our leaderboard with a backlink.
How to embed on WordPress, Wix, Squarespace, Webflow →
WordPress (Gutenberg): Add a "Custom HTML" block, paste the code. Classic editor: switch to "Text" tab, paste.
Wix: Add → Embed Code → Embed HTML → paste. Resize the frame on canvas.
Squarespace: Add block → Code → HTML mode → paste. Click "Apply".
Webflow: Drag an "Embed" element, paste, publish.
Plain HTML: Paste anywhere inside <body>.
Frequently Asked Questions
How accurate is the Gulf of Thailand dive conditions forecast? +
What does the dive condition score mean? +
Why is Sail Rock's score different from Windguru's wind forecast? +
When is the best diving season in Koh Samui and Koh Tao? +
How do I report actual dive conditions to improve the forecast? +
Forecast looking good? Book a trip.
Max 3 students per instructor. Emergency O2 on every boat.
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From Tool To Course
Want to dive these conditions for real?
Forecasts only mean something with someone in the water beside you. Train at the same sites you're tracking.
Max 3 students. Emergency O2 on every boat. Apnea Total certified.