Khao Lak weather in September

September in Khao Lak: sweltering, soaked, with clean air — a gamble, with 26 rainy days.

Updated September 2026 · climate normals from ERA5 reanalysis

Khao Lak🇹🇭 Thailand · Andaman Coast · Beach55
  1. 88Jan
  2. 91Feb
  3. 86Mar
  4. 78Apr
  5. 61May
  6. 65Jun
  7. 63Jul
  8. 60Aug
  9. 55Sep
  10. 56Oct
  11. 68Nov
  12. 83Dec

#12 of 12 months in Khao Lak · #1214 of 1413 destinations to visit in September · comfort 55/100 (tier D)

Days
31°C
Nights
24°C
Wet days
26
Sun
7.9 h
Humidity
88%
Daylight
12 h
Khao Lak, Thailand
Photo: Erik Karits · Pexels

Traveller notes on Khao Lak in September

Notes from nearby Khao Sok (46 km away)

Khao Lak doesn't have its own notes for September yet — these are about Khao Sok, close enough to share the season.

Khao Sok-forum threads asking whether the wetter season is worth it come back strongly positive, posters calling the jungle genuinely at its most vivid this time of year, waterfalls running at full force and the park noticeably quieter than peak season. Regulars describe a typical day as sunny mornings giving way to a real afternoon or evening downpour, though experience varies wildly, one visitor reporting only half an hour of rain a day while another the following week hit a much wetter stretch. September is named among the wettest months here, real planning flexibility standing advice given how unpredictable week-to-week conditions run. Posters call the lake mist and jungle atmosphere genuinely dramatic, a real payoff for travelers willing to accept the risk. Regulars recommend a floating bungalow stay as a highlight regardless of conditions. The record: 28.8C days feeling like a punishing 34C, 23.9C nights, an extraordinarily high 347mm across over 27 days and 91 percent humidity.
KhaoSokSeptemberRegular · September · 1 month ago · about Khao Sok · Read more on Tripadvisor ↗

Other months in Khao Lak

Regulars are specific this marks the start of the dry season here, though real residual rain remains common, any shower typically short-lived and, on a hot afternoon, genuinely welcome rather than disruptive. Our row backs that hot, genuinely wet read, 31.4C reading as a scorching 37C, over 23.6C nights feeling 28C, with a substantial 235.2mm of rain across 24.4 days and humidity at 87 percent. Regulars are consistent tours to the Similan and Surin Islands are back in full swing by this point, restaurants, bars and shops all open again after the quieter wet-season months. Multiple repeat visitors report consistently good weather in mid-November specifically across several different years. The sea sits at a bath-warm 29.8C. The record: 8.2 hours of sun, a 12.9 kph wind and AQI 31.
DrySeasonStartsResidualRainWelcome · November · 1 month ago · Read more on Tripadvisor ↗
Regulars describe this as the tail end of dry season, hot and sunny overall, with afternoon thunderstorms becoming a real possibility as the wet season approaches - when they do arrive, they're usually short and heavy rather than sustained, and regulars note the air and even the humidity level afterward is no worse than earlier in the dry season despite the added moisture. Our row backs the building wetness, 155.7mm of rain across a real 20.8 days, alongside intense heat, 33.1C reading as a hot 40C at 81.5 percent humidity, over 24.7C nights. Regulars call this a good month for value, with online accommodation rates noticeably lower than peak season despite the weather still being broadly enjoyable. The sea holds a warm 30C. The record: 10.4 hours of sun, a 14.4 kph wind and AQI 53.
StormClearsTheAirFastAfterward · April · 1 month ago · Read more on Tripadvisor ↗
December opens the three months regulars rate highest here and they claim it is steadier than the coast further south: clear skies, calm sea, and rarely more than a short shower in a day. Some report a little rain daily and none of it lasting - which is the sense to make of our 99.1mm across 14.6 days, seven millimetres apiece. Their claim that the heat and humidity are moderate holds only against the Thai year: 31.5C at 82 percent reads as 37C, and the sea is 29C, bath water in their phrase. Peak season runs mid-December to mid-January, so the best weather and the highest prices arrive together. The record: 23.2C nights, 9.4 hours of sun and a 14.8 kph wind.
ShortShowerNotAWetDay · December · 1 month ago · Read more on Tripadvisor ↗
March is one of the hottest months in Khao Lak and one of the drier ones, and regulars say visitors usually welcome any rain that arrives because the heat is so high by now. Our row is the most extreme feels-like figure in this collection: 33.3C reading as 39C, with nights at 23.8C that feel like 28C. The 12.4 precipitation days look wrong against a dry month until you see the 74.5mm behind them - six millimetres a wet day, which is the odd afternoon thunderstorm they describe as the wet season approaches from early May. Seas are calm now. What the numbers make plain is that there is no relief in the water: the Andaman is 29.6C, warmer than most swimming pools. December to February is the better weather; March and April are the better value outside Songkran. The record: humidity 76 percent and 10.8 hours of sun.
NoColdWaterToEscapeInto · March · 1 month ago · Read more on Tripadvisor ↗

Add your own note from Khao Lak's card on the map.

Khao Lak climate normals — September

Daytime high31°C / 87°F🔥 sweltering
Nighttime low24°C / 75°F
Feels like (high)36°C / 97°F
Sea temperature29°C / 85°F♨️ bath-warm
Rainfall378 mm / 14.9 in⛈ soaked
Rainy days26 days
Humidity88%💦 very humid
Dew point25°C / 76°F
Sunshine7.9 h/day
Daylight12.2 h
Wind18 km/h / 11 mph
Air quality (US AQI)24🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Khao Lak in September

How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.

Quietschool holidays in 3 of the markets that fill it, one of its worst months for weather(estimated)

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Peak crowdsBusyShoulder seasonQuiet

Best months for Khao Lak's weather

Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).

Toughest weatherKhao Lak's weather peaks January–March, best around February.

September coincides with Southwest monsoon and red flags.

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Best weatherFair weatherToughest weather

What's on in Khao Lak in September

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Season

    Southwest monsoon and red flags

    15 May – 31 Oct · usuallyRip currents & big surf

    Rip currents on this stretch of coast are the real risk, and the red flags go up for weeks at a time. Half the beachfront shuts and the other half drops its rates to nothing.

  • Closure

    Similan and Surin islands closed

    16 May – 14 Oct

    The park authority shuts both island groups for the monsoon every year, which takes the liveaboards and the day boats out with them. Khao Lak's dive shops largely close for the season. Source ↗

  • Season

    Wet season

    MonsoonRisk

    26 rainy days and about 378 mm in the month — the real kind of rainy season, not afternoon showers.

    from the climate normals

What's on around the world in September →

Nearby, and something's on

Within 300 km of Khao Lak — a day trip or a short hop — with something on this month. Never part of the comfort score.

Where is Khao Lak?

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Khao Lak in September — FAQ

Is September a good time to visit Khao Lak?
September in Khao Lak: sweltering, soaked, with clean air — a gamble, with 26 rainy days. It ranks #12 of 12 months for Khao Lak on SeasonMap's comfort score (55/100).
What is the weather like in Khao Lak in September?
In September, Khao Lak averages a daily high of 30.7°C and a low of 23.9°C, with about 378.2 mm of rain over roughly 25.6 rainy days.
What is the air quality in Khao Lak in September?
Khao Lak has a mean US Air Quality Index of about 24 in September.

Within 300 km: Ko Tao's Clear water, dive season around 1 Feb – 30 Sep, and Ko Pha Ngan's Full Moon Party on 1 Jan – 31 Dec.