Sihanoukville sits on a peninsula jutting into the Gulf of Thailand, serving as Cambodia's main gateway to white sand islands and warm turquoise water. The city itself is a launching point for ferries to Koh Rong and Koh Rong Samloem, two islands where coral reefs, bioluminescent plankton, and jungle-fringed beaches reward the short boat ride. Between island trips, you can browse the stalls at Phsar Leu Market for grilled seafood and Khmer dishes like fish amok, climb to the hilltop Wat Leu pagoda for panoramic views over the coastline, or simply settle into the sand at Otres Beach with a cold drink and a sunset ahead of you.
Your best window for Sihanoukville runs from mid-December through early March, when dry skies, calm seas, and the lowest humidity of the year make beach days and island hopping reliably pleasant. January sees rain on roughly 4% of days and humidity sits at its annual low, creating ideal conditions for diving, snorkeling, and ferry crossings to Koh Rong. This is also the quietest stretch for tourism, meaning thinner crowds on the sand and easier accommodation bookings. If you'd prefer a cultural experience and don't mind serious heat, mid-April brings Khmer New Year (Chaul Chnam Thmey), a three-day celebration of temple ceremonies, water splashing, and traditional games that fills the beachfront with energy, though temperatures are at their most intense.
Spring in Sihanoukville, Cambodia
March marks the transition from dry season to wet, and you'll feel it. Early in the month, skies are still mostly clear, but by May showers appear on roughly 40% of days, often rolling in as heavy afternoon bursts that clear within an hour. Highs average 90°F (32.2°C) across the season, the warmest stretch of the year, and the late April peak pushes those to 90.6°F (32.6°C) with overnight lows of 78.4°F (25.8°C). The humidity builds noticeably from March through May, making midday hours on the beach feel sweltering. If you're visiting during this window, plan water activities for the morning, when the air is slightly cooler, and retreat to shade or air conditioning through the hottest part of the afternoon.
The cultural highlight of spring is Khmer New Year, or Chaul Chnam Thmey, a three-day celebration that typically falls in mid-April. Sihanoukville's beachfront fills with locals and visitors joining water-splashing festivities, temple ceremonies at Wat Leu and Wat Krom, and traditional games like tug-of-war. Families prepare dishes such as kralan (sticky rice roasted in bamboo) and amok. Some shops and services close during the holiday, so book transport and accommodation in advance. Lows stay warm at 77.9°F (25.5°C) even at night, so pack the lightest, most breathable clothing you own, a wide-brimmed hat, and strong sunscreen. Tourism volumes are moderate, and you can often find accommodation deals despite the festive atmosphere.
Summer in Sihanoukville, Cambodia
June through August is the heart of Cambodia's monsoon season, and Sihanoukville feels it directly. Rain falls on the majority of days, with precipitation likely 4 to 6 days per week at its peak, often arriving as powerful afternoon storms that can last several hours. The seas become rough, and ferry services to Koh Rong and Koh Rong Samloem face delays or cancellations when swells pick up. If island hopping is a priority, this is the hardest season to plan around. Highs average 87.2°F (30.7°C), a slight step down from spring's scorching peak, but humidity hovers near 80% and makes the air feel thick and heavy.
Despite the weather challenges, summer is actually the busiest tourism season by the numbers, driven largely by international visitors on school holidays. That means higher accommodation prices and more crowded beachfront bars, even as conditions are least favorable for outdoor exploration. Lows of 78.1°F (25.6°C) keep nights steamy. Kbal Chhay Waterfall, about 16 kilometers from the city center, is at its most dramatic during the monsoon when water volume surges, making it worth the bumpy drive along the dirt road. Bring waterproof bags for electronics, quick-dry clothing, and reef-safe sunscreen for the brief windows of sunshine between downpours.
Fall in Sihanoukville, Cambodia
September is the wettest month of the year, with rain likely on roughly 63% of days, and the seas remain rough enough that ferry schedules can be unreliable. But conditions improve steadily from there. By November, precipitation drops to about 34% of days, skies clear more frequently, and the Gulf calms enough for island trips to resume with confidence. Highs average 87°F (30.6°C) through the season, while lows settle to a slightly more comfortable 77°F (25°C) compared to the stifling summer nights. The transition from wet to dry makes late fall particularly appealing for travelers who want decent weather without the peak-season crowds of winter.
Pchum Ben, one of Cambodia's most important spiritual observances, typically falls in late September or early October depending on the lunar calendar. Over 15 days, families visit pagodas to make food offerings honoring their ancestors, and the solemn yet warm atmosphere at local temples like Wat Leu gives you an authentic glimpse into Cambodian Buddhist traditions. Tourism volume remains the second highest of the year through much of fall, though November starts to thin out. This is a solid window for snorkeling and diving once the water clears in late October and November, and Ream National Park's mangrove forests and bird life are lush after months of rain. Pack a lightweight rain jacket and shoes that can handle wet terrain for any inland excursions.
Winter in Sihanoukville, Cambodia
December through February is when Sihanoukville delivers its best version. The dry season is in full swing, with January seeing rain on just 4% of days and February close behind at 6%. Humidity drops to its lowest point of the year, dipping to around 65% in January, and the air feels noticeably lighter than the sticky monsoon months. Highs average 87.6°F (30.9°C), warm enough for full beach days without the oppressive heat of spring. The calm Gulf waters mean reliable ferry crossings to Koh Rong and Koh Rong Samloem, where visibility for diving and snorkeling is at its clearest.
This is the quietest tourism season according to the volume data, with February being the least visited month of the year. That translates to more breathing room on Otres Beach and Ochheuteal Beach, shorter waits for boat tours, and easier restaurant reservations along the Serendipity waterfront. Lows of 74.5°F (23.6°C) make evenings genuinely pleasant for beachside seafood dinners, where grilled prawns, squid, and crab are the local specialties. The Cambodia Sea Festival, a coastal celebration that rotates among Sihanoukville, Kep, Kampot, and Koh Kong each year, typically takes place in December and features concerts, cultural performances, and food stalls along the shore. Bring a light layer for boat rides in the morning breeze, reef shoes for rocky island shorelines, and plenty of sun protection for the consistently clear skies.
At a Glance
Monthly weather, visitor crowds, air quality, holidays, and daylight hours to help you plan your trip.
Travel Tips & Safety for Sihanoukville, Cambodia
Sihanoukville is reachable by bus or taxi from Phnom Penh in about four to five hours, and the city has a small airport with domestic connections. Once there, tuk-tuks and the Grab app are the easiest ways to get around the peninsula. Ferries to Koh Rong and Koh Rong Samloem depart from Ochheuteal Pier multiple times daily during dry season, with the crossing taking roughly 45 minutes. US dollars are widely accepted throughout Cambodia, so there's little need to carry Cambodian riel unless you're making very small purchases from street vendors.
Keep valuables secure and be aware of bag-snatching, particularly on busy beach stretches and after dark. Drink bottled water, exercise normal caution with street food hygiene, and wear reef shoes when swimming near rocky or coral areas. Jet skis operate close to shore at several beaches, so swim in designated areas and stay alert in the water.