Hin Ngam Bay
Hin Ngam Bay is a dive site in Koh Tao, Thailand. Currents typically run at 0.6 km/h and reach 1.2 km/h on the strongest days. Water temperatures range from 28°C in January to 31°C in May. The typical daily tidal range is about 1.3 m. Species recorded in the area include Wire Coral Crab, Amakusa Jelly, Shoulderspot Wrasse, Yellowtail Sergeant and Longfin Bannerfish.
Dive Conditions
Data sources: currents and water temperature from Open-Meteo Marine (CC BY 4.0), hourly model values 2024. Tidal range is the median daily range of modelled sea level from Open-Meteo Marine, hourly values 2024. Species observations from iNaturalist, checked against the World Register of Marine Species.
Conditions at Hin Ngam Bay through the year
Sea surface temperature at the site coordinates, averaged per month from hourly model values for 2024. The water is warmest in May at about 31 °C and coolest in January at about 28 °C, a spread of 3.2 degrees across the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 28.1 | 28.7 | 29.3 | 30.9 | 31.3 | 30.4 | 30.0 | 30.0 | 29.7 | 29.9 | 29.5 | 28.5 |
Ocean current at the site runs at a typical 0.6 km/h. In the strongest tenth of the hours modelled for 2024 it reaches 1.2 km/h, which is when entries are normally timed to slack water at the turn of the tide.
The tide moves the water level by a median 1.3 m over a day, and by up to 1.7 m on the largest days of the month. That range drives how much water is exchanged over the reef and when the current turns.
In the open sea off Hin Ngam Bay, the highest wave of the day exceeded 1.5 m on 3.2 % of days between 2015 and 2024. The roughest month was December (13 % of days), the calmest March (0 %). Land within 10 km blocks some of the directions these waves come from (open to about 54 % of them), so conditions at the site are likely calmer than these open-sea values.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 8 | 2 | 0 | 1 | 0 | 1 | 2 | 2 | 3 | 1 | 5 | 13 |
Satellite habitat mapping places Hin Ngam Bay on an outer reef slope, over a seabed mapped as coral and algae.
How Hin Ngam Bay compares
These comparisons use only the measured values above, set against the 376 dive sites published on findadive.com. A percentage shows the share of other sites with a lower (or higher) value, so it reads the same way wherever the site is.
| Measure | This site | Compared with all sites | Median in Koh Tao |
|---|---|---|---|
| Mean water temperature | 29.7 °C | warmer than 71 % of the other 375 sites | 29.7 °C (34 sites) |
| Water temperature in the coolest month | 28.1 °C | cooler than 54 % of the other 375 sites | 28.1 °C (34 sites) |
| Typical current | 0.6 km/h | weaker than 88 % of the other 375 sites | 0.6 km/h (34 sites) |
| Current in the strongest 10 % of hours | 1.2 km/h | weaker than 86 % of the other 375 sites | 1.2 km/h (34 sites) |
| Median daily tidal range | 1.3 m | smaller than 69 % of the other 375 sites | 1.3 m (34 sites) |
Water temperature, current and tide from Open-Meteo Marine (CC BY 4.0), hourly model values for 2024 at 10.0681°, 99.8411°. Wave statistics from ERA5-Ocean via Open-Meteo Marine (contains modified Copernicus Climate Change Service information 2015–2024), daily maximum wave height on a 0.5° grid; land shelter tested against Natural Earth coastlines. Reef structure and seabed cover from the Allen Coral Atlas © 2018–2023 Allen Coral Atlas Partnership and Arizona State University (CC BY 4.0).
Marine life recorded at this site
Research-grade observations from iNaturalist within about 12 km of these coordinates.
