Best Time to Visit Pig Island

Last updated 25 October 2026 · By the Pig Island Samui team

The best time to visit Pig Island (Koh Madsum) from Koh Samui is January to April, when rain is lowest and the sea is calmest. May to September is also good, with short showers. October to December is Samui’s wet season, with more cancelled trips.

Why is Samui’s weather different?

Samui does not follow the rest of Thailand. Phuket and the Andaman coast get the south-west monsoon from about May to October. Samui sits in the Gulf of Thailand and stays fairly dry then.

Samui’s rain comes later, with the north-east monsoon. October, November and December are the wettest months. November is usually the peak, at about 300 mm of rain. February is the driest, at roughly 40 mm.

Temperatures barely change. Daytime highs run from about 29°C in December and January to about 33°C in April and May. Sea water stays around 28–30°C all year.

Driest monthFebruary

Wettest monthNovember

Sea temperatureAbout 28–30°C

SunsetAbout 17:55–18:45

Pig Island weather and sea by month

This table is our planning guide, based on Samui climate averages and years on the water. Any single day can differ.

Month	Rain	Sea, south coast	Crowds	Our verdict
January	Low	Mostly calm; some windy days	High	Excellent. Book ahead
February	Lowest	Calm	High	Best month overall
March	Low	Calm	Medium–high	Excellent; good snorkelling
April	Low	Calmest winds	Medium–high	Excellent but very hot
May	Moderate	Mostly calm	Medium	Very good; hottest month
June	Moderate	Mostly calm; afternoon breeze	Medium	Very good
July	Moderate	Mostly calm; afternoon breeze	Medium–high	Very good; holiday season
August	Moderate	Mostly calm; afternoon breeze	Medium–high	Very good; holiday season
September	Moderate–high	Mixed	Low	Good; check the forecast
October	High	Choppy days more common	Low	Fair; keep dates flexible
November	Highest	Rough days likely	Low	Hit and miss; book a flexible date
December	High, easing	Windy at times	High after mid-month	Fair early, better late

Jellyfish: Local reports say box jellyfish are most common around Samui from July to October. Snorkel in daylight and wear a long-sleeved rash vest. Read the safety notes in our Koh Tan snorkelling guide.

Morning, afternoon or sunset departure?

We run trips at three times of day. Each has trade-offs.

	Morning	Afternoon	Sunset
Sea	Usually flattest	Breeze can build	Often settles again
Snorkel visibility	Usually best	Good to fair	Fading light
Heat	Cooler start	Hottest hours	Cooling down
Light for photos	Bright, clear	Harsh midday sun	Warm, golden
Meal	Lunch	Lunch or dinner	Dinner on the beach

Our advice: pick a morning trip for snorkelling and young children. Pick the Pig Island sunset tour for photos and a cooler evening. Pickup is 13:00–14:30, and you cross back as the sun goes down.

Tides matter for the reef. At low tide the coral flats near Koh Tan get very shallow. Captains time the snorkel stop around this, so trust their call.

Longtail boat silhouetted at sunset in Thailand — A longtail boat at sunset in the Gulf of Thailand.

What happens if the weather cancels my trip?

Safety comes first. The captain decides on the morning, based on wind, swell and storms. If the captain cancels for weather or sea safety, you choose: a full refund or a new date.

Light rain alone rarely stops a trip. Strong wind and big swell do. If you cancel yourself, our normal terms apply:

48 hours or more before departure: full refund
24 to 48 hours before: 50% refund
Under 24 hours, or no-show: no refund

Bookings are confirmed by email and WhatsApp after payment. Full details are in our booking terms.

Tip: In October to December, book your trip early in your stay. If the weather cancels it, you still have days left to rebook.

Ang Thong is closed 1 November to 15 December

Ang Thong Marine Park closes every year from 1 November to 15 December. The break lets the park recover and avoids the roughest monsoon seas. Exact dates can shift with the weather.

During those six weeks, Pig Island becomes the main island-hopping trip from Samui. Trips run whenever the sea allows. The south-coast islands are close to shore, so the crossing is short. When Ang Thong reopens, our sister site angthongmarinepark.com runs tours there. Not sure which to choose? Read Pig Island vs Ang Thong.

Staying on the next island? Our Koh Phangan weather guide covers the same monsoon from Phangan’s side. You can also join from there; see Pig Island from Koh Phangan.

What to pack, by season

January to September

Reef-safe sunscreen and a hat
Long-sleeved rash vest
Sunglasses
Swimwear and a towel
Cash for the island fee and drinks
Water bottle

October to December

Light rain jacket
Dry bag for phone and cash
Seasickness tablets if you need them
A spare dry top for the ride back
Rash vest and sunscreen; the sun still burns
Flexible dates

The island fee on Koh Madsum is about 50 THB per person, cash, paid on the island (last checked October 2026). For full costs, see Pig Island prices.

Questions

Weather and timing FAQ

What is the best month to visit Pig Island?

February is usually the best month. It is the driest month on Koh Samui and the sea is generally calm. January, March and April are close behind. These months are also the busiest, so book a few days ahead. You can compare every option on our Pig Island tours page.

Can I visit Pig Island in the rainy season?

Yes. Trips run from October to December whenever the sea is safe. Expect more showers and some cancelled days, especially in November. If the captain cancels for weather, you choose a full refund or a new date. Book early in your stay so you have spare days. See our booking terms.

Is morning or afternoon better for Pig Island?

Morning is better for snorkelling, because the sea is usually flatter and the water clearer. Afternoon and sunset trips are cooler later on and better for photos. Families with young children often prefer mornings. Our speedboat tour runs both morning and afternoon.

Does rain cancel the boat trip?

Light rain rarely stops a trip. Strong wind, big swell and storms do. The captain decides on the day, with safety first. If we cancel, you choose a full refund or a new date. Message us on WhatsApp the evening before if the forecast worries you. More answers are in our FAQ.

Is Pig Island open when Ang Thong is closed?

Yes. Ang Thong Marine Park closes every year from 1 November to 15 December. Pig Island trips keep running in that period, weather permitting. That makes Koh Madsum and Koh Tan the main island-hopping choice from Samui then. Read Pig Island vs Ang Thong to compare.

What time is sunset on Koh Samui?

Sunset falls between about 17:55 in November and December and about 18:45 in July. Our sunset tour picks you up between 13:00 and 14:30, so you are on the water as the light turns gold. Dinner is at a beach restaurant. See the Pig Island sunset tour.

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