Koh Lanta · Month comparison

September vs March

March ranks #1 overall vs September at #12. Still excellent — dry season holds, crowds ease, prices begin to soften.

Koh Lanta September — peak monsoon at 260mm with rough Andaman Sea and rain-lashed coast

September

#12 of 12 months

Avoid

The wettest month of the year at 260mm — hard cap forces a weather score of 2.

  • Cheapest possible prices on accommodation — almost nothing left open to charge for
  • Waterfalls in the Mu Koh Lanta national park reach their peak flow
Koh Lanta March — sunny beach in Ko Lanta with traditional wooden boats on golden sand

March

#1 of 12 months

Best match

Still excellent — dry season holds, crowds ease, prices begin to soften.

  • 45mm rainfall remains very dry — weather still overwhelmingly reliable and sunny
  • High season crowds thinning as European winter holidays end, making beaches more enjoyable
FactorSeptemberMarch
Weather score
2
9
Value score
9
5
Crowd score
9
5
Events score
3
5
Atmosphere
4
8
Avg high temp30°C33°C
Monthly rain260mm45mm
Daily sunshine4.5hrs9hrs

September trade-offs

  • 260mm exceeds 250mm: the absolute worst weather cap — this is a mandatory avoid for any weather-sensitive trip
  • Road flooding common — access to the southern national park unreliable
  • Essentially every business on the island is closed: this is genuine ghost-town mode

March trade-offs

  • Temperatures hitting 33°C by midday — less comfortable for active days than Feb
  • Some early monsoon showers possible in the last week as the Andaman begins to stir
  • Sea still calm but visibility at diving sites marginally less crystal than February
Scores compare months within Koh Lanta. Climate data: Open Meteo ERA5 30-year normals (1991–2020). Methodology →