Month-specific sea-surface temperature · Cambodia

Koh Rong Sea Temperature in September

29.5°C

85.1°F

In September, sea-surface temperature near Koh Rong has a historical monthly average of 29.5°C. This is not the reading for any particular holiday date.

Across 2023–2025, the lowest and highest yearly September monthly means were 29.3–29.7°C. These are not daily extremes.

Previous month

August · 29.8°C

Change into September: -0.3°C

Next month

October · 30.0°C

Change into next month: +0.5°C

Can you swim or snorkel in Koh Rong in September?

At 29.5°C our temperature-only guide describes the water as very warm water. Comfort depends on your cold tolerance, immersion time and wind. A historical average cannot determine whether conditions are safe on any given day.

Do you need a wetsuit?

Swimwear is usually enough; a rash guard adds sun protection.

Which beach should you choose?

Look for a beach sheltered from the actual forecast waves and wind on your visit. Exposure, currents and entry conditions vary even where water temperatures are similar. Follow local warnings.

Check the current waves, wind and snorkeling forecast →

A live forecast does not predict a future September. Check again close to your trip.

Koh Rong Sea Temperature: All 12 Months

Choose a month for available historical evidence, month comparisons and swim guidance. Missing history is clearly marked and never presented as a long-term normal.

January 29.0°C February 29.3°C March 29.9°C April 31.1°C May 31.4°C June 30.1°C July 29.6°C August 29.8°C September 29.5°C October 30.0°C November 30.0°C December 29.4°C

Data source and limitations

Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature; 2023–2025. Marine model grid near 10.72, 103.24. Based on 3 yearly monthly means and 2160 recorded samples. Source methodology.

Modelled sea-surface temperatures do not establish underwater visibility, wildlife, calm currents or safe entry.