Here is the thing most couples don’t realise: Krabi and Koh Samui sit on opposite coasts of Thailand, with genuinely different weather. Picking the right month means knowing which coast you’re on.

Two coasts, two patterns

Krabi is on the Andaman (west) coast. Koh Samui is in the Gulf of Thailand (east) coast. They do not share a season — which is genuinely useful, because if your ideal date falls in one coast’s wet spell, the other may be perfect.

Krabi: best November to March

Krabi’s dry season runs roughly November through March, with the most reliable sunshine and calmest seas for island-hopping in December–February. This is peak — stunning weather, highest demand, book early. April is hot and still largely dry; the wetter months build from May, peaking around September–October.

Best for a Krabi beach wedding

  • Sweet spot: December–February — dry, clear, calm seas.
  • Great value: November and March — lovely weather, a touch quieter.
  • Avoid for outdoor: September–October, the wettest window.

Koh Samui: best January to April (and a good mid-year window)

Samui’s gulf pattern runs later. Its driest, brightest stretch is January to April, and it also enjoys a pleasant mid-year window around June–August when the Andaman coast is wetter. Samui’s rainy season comes late — the wettest months are typically October–November, exactly when much of the rest of Thailand is drying out.

Best for a Koh Samui beach wedding

  • Sweet spot: January–April — the most reliable sunshine.
  • Strong alternative: June–August — good on Samui while the Andaman is wet.
  • Avoid for outdoor: October–November, Samui’s wettest window.

If your date is fixed, let it choose your coast: a February wedding suits either, but an October wedding leans Krabi-dry-ish is out — look to earlier, and a mid-year date clearly favours Samui.

A note on “rainy season”

Thai rain in shoulder months is often a dramatic afternoon downpour, not all-day grey — mornings and evenings can be glorious. Shoulder-season weddings can be beautiful and better value, provided you build a weather contingency (a covered plan B) into the day. That is exactly the kind of call a local planner makes with you.