Haad Than Sadet sea temperature today: 30°C – beach water temperature, Haad Than Sadet, Thailand
Interactive map
Thailand · Koh Phangan
Haad Than Sadet
Sea
29.7°C85.5°F
Air
–
UV
–
Bathtub
Above ⁦28°C⁩

Last updated ·

Today, September 13, the sea temperature at Haad Than Sadet is 29.7 °C (85 °F). That matches the usual average of 29.5 °C in September. Comfortable for swimming year-round.

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Climate · monthly averages

Sea temperature by month

5-year averages (2021–2025). Min/Max are typical daily lows and highs, not record extremes.

Warmest in May (30.8°C). Coldest in January (27.8°C). Comfortable for swimming year-round.

5-year averages (2021–2025). Min/Max are typical daily lows and highs, not record extremes.
MonthSea · MinSea · AvgSea · MaxAir · MinAir · AvgAir · Max
January27.3°C27.8°C28.6°C26.5°C26.8°C26.9°C
February28.1°C28.4°C28.9°C26.8°C27.1°C27.2°C
March28.6°C29.1°C29.6°C27.5°C27.8°C28.0°C
April30.2°C30.4°C30.9°C28.2°C28.6°C28.9°C
May30.2°C30.8°C31.4°C28.4°C28.8°C29.1°C
June29.9°C30.2°C30.5°C28.0°C28.5°C28.9°C
July29.6°C29.8°C30.0°C27.8°C28.3°C28.7°C
August29.4°C29.8°C30.2°C27.5°C28.1°C28.5°C
September29.3°C29.5°C29.7°C27.3°C27.8°C28.1°C
October28.9°C29.4°C29.8°C26.9°C27.4°C27.7°C
November28.4°C28.9°C29.4°C26.7°C27.1°C27.3°C
December27.5°C28.0°C28.6°C26.6°C27.0°C27.1°C

About Haad Than Sadet

Ko Pha-ngan sits in the Gulf of Thailand off Surat Thani, and its eastern jungle culminates in Than Sadet National Park, where boulders along the stream carry the royal initials Thai kings have carved since Rama V's 1888 visit. On the southern peninsula, Haad Rin draws thousands to its monthly Full Moon Party, while Haad Mae Haad on the northwest coast links to tiny Koh Ma by a tied-island sandbar at low tide. The sea stays at 28–29 °C82–84 °F year-round; Samui airport is a 30-minute ferry away.

Frequently asked questions

Today, September 13, the sea at Haad Than Sadet is 29.7 °C (85 °F)85 °F (29.7 °C) – bathtub-warm. The usual September average is 29.5 °C85 °F.

No single number works for everyone, so the scale on this page is only a guide to how the water feels: below 13 °C55 °F icy, 13–18 °C55–64 °F cold, 18–23 °C64–73 °F refreshing, 23–28 °C73–82 °F pleasantly warm and above 28 °C82 °F like a bath. Right now the sea at Haad Than Sadet is 29.7 °C85 °F.

Yes – the sea at Haad Than Sadet (Koh Phangan, Thailand) stays swimmable all year. January is the coolest month, averaging 27.8 °C82 °F – ideal for swimming for most people; the warmest is May at 30.8 °C87 °F.

In May, at 30.8 °C87 °F on average. The coolest month is January at 27.8 °C82 °F – still above the 18 °C64 °F swimming line, so there is no off-season for swimming.