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Sanya, on the southern tip of China’s Hainan Island, has a tropical monsoon climate with warm temperatures year-round and a distinct wet-dry seasonal pattern. For more context, read our best time to visit Sanya guide. The city averages 25.6°C (78°F) annually and receives about 1,588mm (62.5 inches) of rainfall, nearly all of it falling between May and October. Sea temperatures stay between 23°C and 29°C (73-84°F), making swimming possible in every month.
Sanya Weather by Month: January
January is Sanya’s coolest month with daytime highs around 21°C (70°F) and overnight lows of 18°C (64°F). For more context, read our things to do in Sanya guide. Rainfall averages just 9mm (0.35 inches) across 3 rainy days. Sea temperature is 23°C (73°F) , cool but swimmable. This is peak tourist season with Chinese New Year often falling in late January or February, sending hotel prices to their annual maximum. Sunshine averages 6 hours per day.
Sanya Weather by Month: February
February warms slightly to 22°C (72°F) highs and 19°C (66°F) lows. For more context, read our Sanya events and festivals guide. Rainfall remains low at 13mm (0.5 inches). Chinese New Year celebrations dominate the month when they fall here, pushing occupancy to near 100% and room rates 2-3x normal. Book at least 3 months ahead if visiting during Spring Festival. Sea temperature holds at 23°C (73°F).
Sanya Weather by Month: March
March brings 24°C (76°F) highs and 21°C (70°F) lows. For more context, read our best neighborhoods in Sanya guide. Rainfall increases slightly to 19mm (0.75 inches). The weather is reliably sunny with about 7 hours of daily sunshine. This is an excellent month to visit: peak-season crowds thin after Chinese New Year but the weather remains dry and pleasant. Sea temperature rises to 24°C (75°F).
Sanya Weather by Month: April
April reaches 27°C (81°F) during the day and 24°C (75°F) at night. For more context, read our where to stay in Sanya guide. Rainfall jumps to 46mm (1.8 inches) as the wet season approaches, but mornings are typically clear with afternoon showers. This is the last reliably dry month before the monsoon. Hotel prices are moderate. Sea temperature reaches 26°C (79°F).
Sanya Weather by Month: May
May marks the start of the wet season with 135mm (5.3 inches) of rain. For more context, read our Sanya travel tips guide. Daytime highs reach 29°C (85°F) and lows stay at 26°C (79°F). Humidity climbs past 80%. You will get beach days but expect short, heavy downpours most afternoons. This is the start of the low season with hotel rates dropping 30-50% from winter peaks. Sea temperature is 28°C (82°F).
Sanya Weather by Month: June
June sees 195mm (7.7 inches) of rainfall with 29°C (85°F) highs. Check the full Sanya city guide for an overview of the city. Typhoon season technically begins though direct hits on Sanya are rare this early. The rain comes in intense bursts, often in late afternoon, leaving mornings free for outdoor activities. Hotel prices are at their lowest outside of the typhoon-risk months. Sea temperature peaks at 29°C (84°F).
Sanya Weather by Month: July
July is Sanya’s second-wettest month at 202mm (8 inches) and the hottest at 29°C (84°F) with 26°C (79°F) lows. Typhoon risk is moderate , Hainan sees an average of 1-2 typhoons per year and July-September is the window. Domestic summer holiday travel keeps occupancy reasonable despite the rain. Sunshine averages 8 hours between storms.
Sanya Weather by Month: August
August averages 222mm (8.7 inches) of rain with 28°C (83°F) highs. This is the wettest and most humid month. Typhoon probability peaks in August. Despite the numbers, many days are warm and sunny with short afternoon downpours rather than all-day rain. Sea temperature is 29°C (84°F). Chinese summer holidays keep some demand but prices are still 40-50% below winter.
Sanya Weather by Month: September
September is the rainiest month at 268mm (10.6 inches) with 28°C (82°F) highs. This is peak typhoon season and the one month where travel insurance with weather coverage is recommended. The rain pattern shifts toward longer multi-day systems rather than brief afternoon storms. Sea temperature remains 28°C (82°F). Hotel prices hit their annual floor , you can find 5-star rooms under CNY 500 (US$70).
Sanya Weather by Month: October
October brings 213mm (8.4 inches) of rain but marks the transition back toward dry season. Highs reach 27°C (80°F). The first half can still be wet; the second half typically sees improving conditions. Typhoon risk drops sharply after mid-October. This is a shoulder month with good value , drier than summer but cheaper than winter. The Golden Week holiday (first week of October) causes a brief price spike.
Sanya Weather by Month: November
November is the start of the dry season and the beginning of peak tourism. Rainfall drops to 62mm (2.4 inches). Highs are 25°C (77°F), lows 21°C (70°F). This is arguably the best month for weather: warm enough for the beach, dry, and before the Christmas/New Year price surge. Sea temperature is 26°C (79°F). Book 4-6 weeks ahead.
Sanya Weather by Month: December
December delivers 22°C (72°F) highs and 18°C (64°F) lows with just 21mm (0.8 inches) of rain. Sea temperature drops to 24°C (75°F). The Christmas to New Year period is the second-most expensive booking window after Chinese New Year. Russian and Northern European tourists flock here to escape winter. Sunshine averages 6 hours daily.
