Samui Weather in March: 30.4°C, 115 mm Rain, 29°C Sea

Is March a Good Time to Visit Koh Samui?

Yes. Samui weather in March combines 7.5 hours of sunshine a day (tied with February for the sunniest month of the year) with a warm 30.4°C average high and calm, swimmable seas at 29.0°C. Rainfall sits at 115 mm, more than February’s 65 mm, but across only 5 rain days, so most of the month runs dry and bright. March is also the last stretch before April’s heat becomes the season’s real tipping point, making it a strong window for active days as well as beach time.

Key takeaways

• 7.5 sun hours/day ties February for the year’s sunniest month, on just 5 rain days
• 115 mm of rain is heavier than February’s 65 mm, but compressed into fewer, harder downpours: sunnier, not drier
• 30.4°C highs are comfortable; April’s 31.8°C is where many visitors feel the shift to hot season
• Sea holds at 29.0°C, calm enough for reliable Ang Thong trips and ferries to Koh Phangan and Koh Tao
• Waterfalls are near their lowest flow of the year after months without heavy rain
• Prices ease from the January-February peak while the weather still holds

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Koh Samui Weather in March: The Numbers

Koh Samui’s March climate sits between February’s driest stretch and April’s heat spike, based on climatestotravel.com’s 1991-2020 climate normals (cross-checked Sep 2026), the same long-run station data used across this site’s best time to visit guide.

Other sites print different March figures (TUI, for example, quotes roughly 80 mm of rain): climate normals differ by station and averaging period, so treat the rain total as a range of about 80-115 mm and the pattern (few rain days, lots of sun) as the reliable part.

March is a transition month in both directions: it is warmer and slightly wetter than February, but still sunnier than April, which loses a full sunshine hour as afternoon cloud builds ahead of the wet season. No other month matches March’s combination of peak sunshine and comfortable heat.

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How Hot Is Koh Samui in March?

Expect about 30.4°C (86.7°F) by day and 25.4°C (77.7°F) at night, a mean of 27.9°C, with the sea at 29.0°C. That is 1.0°C warmer than February by day and 1.4°C cooler than April’s 31.8°C highs. Sites that list a March range of 25-32°C are describing the same month: the low end is the night, the high end is an exposed afternoon.

Day-to-day this means hot, bright middays and warm nights. Plan walking, stairs and viewpoints for the morning or late afternoon, and keep the midday hours for the beach or a pool.

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Sunny But Heavy: March’s Honest Rain Trade-Off

March is not drier than February: it is sunnier despite being wetter. February’s 65 mm falls across 4 rain days; March’s 115 mm falls across only 5, so each March rain day dumps roughly 23 mm on average against February’s 16 mm. In practice this means a shorter list of rain days but a harder downpour when one hits, usually a 30-60 minute afternoon squall rather than a gray, drizzly stretch. Koh Samui’s true rainy season, from September through December, runs the opposite way: more rain days, and eventually less sun per day than March keeps even on its wetter afternoons.

The practical read: pack for five possible downpours, not daily rain, and expect any one to be short and intense rather than a lost day.

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The Sweet Spot Before April’s Heat

March’s 30.4°C average high is the last genuinely comfortable temperature before Koh Samui’s hot season takes over: April’s 31.8°C is the point where many visitors first feel the heat shift from pleasant to demanding. That 1.4-degree jump shows up first on exposed activities: a temple staircase, a shadeless viewpoint, or a full afternoon walking Fisherman’s Village. March still allows a full day outdoors without the early starts and shade-chasing April and May require.

This makes March the better month, out of the two, for anyone planning a hiking or temple-heavy itinerary rather than a pure beach trip. See the best time to visit guide for how the hot season builds from here through May.

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Best Beaches and Sea Conditions in March

March’s sea temperature of 29.0°C and calm conditions make it one of the best months on Samui for swimming, snorkeling and boat trips, according to this site’s own sea conditions by month guide, which rates every coast “calm” in March: the only stretch of the year every side of the island gets that rating at once. Chaweng Beach and Lamai Beach have fully recovered from the previous year’s monsoon swell, and north-coast beaches like Maenam and Bophut stay their usual flat, shallow selves.

Calm seas also mean March is a reliable month for Ang Thong National Marine Park day trips and ferries to Koh Phangan and Koh Tao: cancellations for rough water are rare compared to the September-November monsoon window. Snorkeling visibility is generally good, aided by low sediment runoff after months of light rain.

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Waterfalls, Hiking and Temples in March

Koh Samui’s waterfalls are honestly near their lowest flow of the year in March, the flip side of the dry season that makes the beaches and boat trips so reliable. Na Muang Waterfalls and Hin Lad Waterfall depend on the October-January monsoon recharge covered in the waterfalls and hikes guide, and by March that water has mostly drained through: expect a thinner curtain of water than photos taken in December or January.

Hiking and temples fare better. March’s comfortable 30.4°C highs, still short of April’s heat, suit the Na Muang Waterfalls Trail and Hin Lad Waterfall Trail even with lower water, and shadeless routes are still manageable if started early. Temple visits are a strong pick this month: Wat Phra Yai, home of the Big Buddha, and the hillside Secret Buddha Garden both involve open stone and stairs, noticeably easier at March’s temperatures than at April or May’s. The temples guide covers the full island list.

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Events in March

March is a quiet month on Koh Samui’s event calendar: no fixed island-wide festival lands in this window, unlike April’s Songkran or the Christmas and New Year fortnight. Makha Bucha (a nationwide alcohol-ban day) fell on 3 March in 2026 and moves to 21 February in 2027, so a March 2027 trip has no ban day; see the Buddhist holidays and alcohol-ban calendar. The Koh Phangan Full Moon Party is on Monday 22 March 2027 (check the page again within a week of travel, dates can shift).

Outside of that recurring party, March suits travelers who want dry-season weather without a festival crowd stacked on top of it.

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Prices and Crowds in March

Koh Samui’s prices ease noticeably in March compared with the January-February peak, even though the weather barely changes. The best time to visit guide notes crowds and rates “stay busy but ease slightly once the holiday crowd disperses” through February and March, as the Chinese New Year and school-holiday overlap gives way to steadier demand. Beaches and restaurants feel less packed than in January, without the deep discounting that only really kicks in from September onward.

March is arguably the best value month on the calendar: dry-season-quality sun and sea at a price already down from the year’s peak. The trip cost guide breaks down a March week by budget tier, and the when to book guide covers how far ahead to lock in flights and rooms.

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What to Pack for Koh Samui in March

Pack for warm, sunny days with a low but real chance of a hard afternoon downpour: light, breathable clothing, reef-safe sunscreen and a hat for the strong March sun, plus a packable rain jacket for one of the month’s 5 rain days. Swimwear and water shoes cover both beach days and rockier shore entries around Ang Thong. Since late March starts to feel more humid as the hot season builds, quick-dry fabrics are worth prioritizing over anything heavy. The full packing list guide covers the rest of a standard Koh Samui kit.

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February, March or April: Which Should You Pick?

All three sit inside or right at the edge of Koh Samui’s dry-to-hot season, but each trades differently. February is driest and coolest of the three, with the fewest rain days. March matches February’s sunshine hours while running a touch warmer and wetter, and it is the last month before April’s heat becomes the defining feature of a trip. April brings the warmest sea (30.0°C) but also the first real heat tipping point at 31.8°C highs, plus Songkran crowds. For most travelers balancing comfort, sun and price, March is the sweet spot between the two. The full year-round breakdown is in the best time to visit guide.

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FAQ

Is March a good month to visit Koh Samui?

Yes. March ties February for the year’s sunniest month at 7.5 hours a day, keeps a comfortable 30.4°C average high, and offers calm, swimmable seas at 29.0°C across every coast. Rainfall (115 mm over 5 days) is higher than February’s but falls in fewer, harder downpours rather than steady drizzle.

Does it rain a lot in Koh Samui in March?

Not much overall, but each rain day counts more than in February. March averages 115 mm across just 5 rain days, versus February’s 65 mm over 4 days: meaning March’s rain is heavier per shower, typically a short, intense afternoon squall rather than an all-day washout.

Is the sea warm enough to swim in Koh Samui in March?

Yes. March’s sea temperature of 29.0°C is warm and calm, and this site’s own sea conditions by month guide rates every coast on the island “calm” in March: the only month with that rating everywhere at once, making it a reliable month for Ang Thong trips and ferries.

Are Koh Samui’s waterfalls worth visiting in March?

Not at their best. Na Muang and Hin Lad rely on monsoon recharge from the previous October-January window, and by March that flow has largely drained through. Visitors chasing full waterfalls should target October through January instead; hiking the trails themselves is still pleasant in March’s cooler-than-April heat.

What is the rainiest month in Koh Samui?

November, at about 445 mm over 16 rain days, is the wettest month on Koh Samui, followed by October (about 295 mm). March’s 115 mm is a fraction of that, and February is the driest month at 65 mm. The rainy season guide has the full month-by-month table.

Which month should you avoid on Koh Samui?

Avoid November if you want reliable sun, and treat October as a gamble. March sits in the dry-to-hot stretch and is not a month to avoid: the only reason to skip it is a dislike of heat, which builds further in April and May.

Is March a good month to visit Thailand?

Yes for the beaches on both coasts. March is dry on the Gulf side (Koh Samui, Koh Phangan, Koh Tao) and on the Andaman side (Phuket, Krabi), so it works for a two-coast trip.

Is March better than April on Koh Samui?

For most travelers, yes. March keeps April’s warm sea temperature trend without April’s 31.8°C heat tipping point, and it still matches February’s peak sunshine hours. April does offer the warmest sea of the year (30.0°C) but adds Songkran crowds and noticeably more demanding heat for hiking or temple days.

Are Koh Samui prices lower in March than in January or February?

Somewhat. March prices ease from the January-February holiday peak as Chinese New Year and school-holiday demand fade, though the drop is gradual rather than sharp. Travelers chasing the steepest discounts should look toward the shoulder season or the September-October low season instead, but March offers a reasonable middle ground between weather and cost.