Sea temperature in China
Live water temperatures and swimming conditions across 3 beaches on the China coast.
Best time to swim in China
The sea in China peaks in May, when the water averages around 29°C.
The main swimming season runs from January – December, when surface temperatures stay comfortable for extended sessions.
On average, 12 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
The coldest month is typically January at around 26°C, when cold-water swimmers dominate the coast.
China sea temperature history
Long-term climatology for China shows an annual mean sea temperature of 28°C, ranging from 26°C in winter to 29°C at the summer peak.
The seasonal swing is roughly 3°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.
Recent decades have trended slightly warmer at China, in line with regional sea-surface temperature records for the wider basin.
Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.
Values are area averages; individual beaches vary by exposure and depth.
China sea temperature: frequently asked questions
What is the warmest month to swim in China?
May is the warmest month in China, when the sea averages about 29°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in China?
The coldest month in China is typically January, when the water averages around 26°C. Cold-water swimmers and surfers dominate this period.
When can you swim in China without a wetsuit?
The main swimming season in China runs from January – December — about 12 months a year when the sea sits above 20°C, the level most swimmers describe as pleasant without a wetsuit.
Do I need a wetsuit in China?
China stays warm year-round, so most swimmers never need a wetsuit — a rash guard is usually enough for sun and wildlife protection.
What is the average sea temperature in China?
The long-term annual mean sea temperature in China is about 28°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in China?
The live reading at the top of this page shows the current sea temperature in China, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
China sea temperature by month
Average sea temperatures around China for every month of the year, based on long-term Open-Meteo marine climatology.
| Month | Average sea | Swimming comfort |
|---|---|---|
| January | 26.0°C | Warm swimming |
| February | 26.0°C | Warm swimming |
| March | 27.0°C | Very warm, bath-like |
| April | 28.0°C | Very warm, bath-like |
| May ⭐ | 29.0°C | Very warm, bath-like |
| June | 29.0°C | Very warm, bath-like |
| July | 29.0°C | Very warm, bath-like |
| August | 28.0°C | Very warm, bath-like |
| September | 28.0°C | Very warm, bath-like |
| October | 28.0°C | Very warm, bath-like |
| November | 27.0°C | Very warm, bath-like |
| December | 26.0°C | Warm swimming |
Monthly figures are modelled climatology averages, not live readings. How accurate is our data?
Warmest beaches in China right now
| Beach | Region | Sea | Swim score |
|---|---|---|---|
| Sanya Bay | Hainan | 28.2°C | Excellent |
| Dadonghai Beach | Hainan | 27.7°C | Excellent |
| Yalong Bay | Hainan | 27.5°C | Excellent |
Sea temperature in China — FAQ
How warm is the sea in China in September?
The sea off China averages about 28.0°C in September, based on long-term monthly averages for this coast.
When is the best time to swim in China?
China is warmest in May (around 29.0°C) and coldest in January (around 26.0°C). There are typically 12 months a year when the water sits above 22°C.
What is the average yearly sea temperature in China?
Across all twelve months, the sea in China averages about 27.6°C.
Do you need a wetsuit to swim in China?
In peak season (around May, ~29.0°C) most swimmers are comfortable without a wetsuit. Outside summer, when the water drops toward 26.0°C, a 3/2mm to 5/4mm wetsuit is recommended.