Sihanoukville weather in September
September in Sihanoukville: sweltering, soaked, with clean air — a gamble, with 29 rainy days.
Updated September 2026 · climate normals from ERA5 reanalysis
#12 of 12 months in Sihanoukville · #1241 of 1413 destinations to visit in September · comfort 53/100 (tier D)
- Days
- 28°C
- Nights
- 25°C
- Wet days
- 29
- Sun
- 7 h
- Humidity
- 86%
- Daylight
- 12 h
Traveller notes on Sihanoukville in September
Other months in Sihanoukville
Sihanoukville forum regulars describe August as genuine monsoon season, with rain that can hit overnight, early morning or mid-afternoon and, when it does, comes down hard for roughly an hour before clearing. One traveler who spent two weeks there in August said it only rained a handful of times, always torrential but brief, and had more sunny days than wet ones overall. The bigger risk isn't the rain itself but rougher seas - a few posters mentioned island boat trips to Koh Rong getting cancelled on choppy days, so it's worth building a spare day into any island-hopping plan.
Forum posters describe February as comfortably inside Cambodia's dry season, with beaches around Sihanoukville generally clean and calm this time of year. Posters are candid, though, that the country's tropical climate means even peak dry season isn't fully rain-free - localized afternoon or evening showers and brief thunderstorms remain possible, following a common daily pattern of a sunny morning giving way to clouding and rain later in the day. Posters treat this as a minor, short-lived interruption rather than a reason to avoid the period, with February still ranking among the better months for beach time on this coast.
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Sihanoukville climate normals — September
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Sihanoukville 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)
Peak crowdsBusyShoulder seasonQuiet
Best months for Sihanoukville'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 weatherSihanoukville's weather peaks December–February, best around January.
Best weatherFair weatherToughest weather
What's on in Sihanoukville in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Season
Rough island crossings
1 Jun – 15 Oct · usuallyOff-season shutdownClosuresSouthwest wind puts a short chop on the run out to the islands and the ferries get cancelled on the bad days. Plenty of the island guesthouses simply close until November.
- Festival
Pchum Ben
10 Sep – 10 Oct · usuallyReligious feastClosuresFifteen days of dawn offerings ending in a three-day national holiday; the town's Khmer staff go home and services thin out for the week. Source ↗
- Season
Wet season
MonsoonRisk29 rainy days and about 530 mm in the month — the real kind of rainy season, not afternoon showers.
from the climate normals
Nearby, and something's on
Within 300 km of Sihanoukville — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Sihanoukville?
Sihanoukville in September — FAQ
- Is September a good time to visit Sihanoukville?
- September in Sihanoukville: sweltering, soaked, with clean air — a gamble, with 29 rainy days. It ranks #12 of 12 months for Sihanoukville on SeasonMap's comfort score (53/100).
- What is the weather like in Sihanoukville in September?
- In September, Sihanoukville averages a daily high of 28.2°C and a low of 25.3°C, with about 530.4 mm of rain over roughly 28.8 rainy days.
- What is the air quality in Sihanoukville in September?
- Sihanoukville has a mean US Air Quality Index of about 30 in September.
Within 300 km: Phnom Penh's Pchum Ben around 10 Sep – 10 Oct, and Phu Quoc's Phu Quoc visa exemption on 1 Jan – 31 Dec.