Sihanoukville sits on Cambodia's southern coast along the Gulf of Thailand, serving as the country's premier beach gateway and the main launching point for island hopping to Koh Rong and Koh Rong Samloem. The city is equal parts working port and tropical playground, where white-sand beaches line the western coastline, fresh seafood barbecues sizzle along the shore, and fast ferries shuttle travelers to some of Southeast Asia's most untouched islands. Beyond the beaches, you'll find hilltop Buddhist pagodas, a lively local market called Phsar Leu, and the kind of relaxed coastal energy that makes it easy to extend your stay.
Your best window runs from mid-December through early March, when Sihanoukville's dry season delivers reliably sunny skies and the calmest seas for island hopping and diving. January sees rain on just 4% of days and February on only 6%, giving you long stretches of uninterrupted beach time. Humidity drops to its lowest levels of the year, and the warm but manageable highs of 87.6°F (30.9°C) feel more comfortable with lower moisture in the air. This is also the quietest period for tourism, meaning thinner crowds on the beaches and better deals on accommodation. If your schedule doesn't fit that window, November works as a shoulder option: the monsoon is winding down and prices haven't climbed yet for the peak dry season.
Spring in Sihanoukville City Centre, Cambodia
March through May marks the transition from dry season into monsoon, and it's also when Sihanoukville hits its hottest temperatures. Highs average 90°F (32.2°C) across these months, and mornings rarely drop below 77.9°F (25.5°C), so the heat is relentless day and night. Late April pushes temperatures to their annual peak, with highs reaching 90.6°F (32.6°C) and lows of 78.4°F (25.8°C). If you visit during mid-April, you may catch Khmer New Year celebrations, when Cambodians flock to the beaches and hilltop pagodas like Wat Leu become especially lively with prayer ceremonies and family gatherings.
Rain starts creeping in as the season progresses. March remains fairly dry with only a 21% chance of significant rain on any given day, but by May that climbs to 40%, with afternoon downpours that can be heavy but typically pass within an hour or two. The rising humidity, which reaches 75.9% by May, makes the heat feel more oppressive. Tourism stays relatively slow during this stretch, so accommodation deals are available, particularly in March and April before the monsoon fully arrives.
This is still a workable time for snorkeling and boat trips to Koh Rong, especially in March when seas remain calm. By May, swells start building and visibility underwater diminishes. Pack lightweight, breathable clothing and reef-safe sunscreen, and plan outdoor activities for the morning hours when the air feels slightly cooler.
Summer in Sihanoukville City Centre, Cambodia
June through August is full monsoon season in Sihanoukville, and the weather shapes everything about your trip. Rain falls on roughly half the days, with June at 48%, July at 55%, and August at 51% chance of significant precipitation. Showers tend to arrive in powerful afternoon bursts that can flood low-lying roads and turn beach sand into soup. Humidity hovers near 80% through the entire season, and highs average 87.2°F (30.7°C) with lows of 78.1°F (25.6°C), keeping the air thick and steamy around the clock.
Rough seas during these months regularly disrupt ferry service to Koh Rong and Koh Rong Samloem, so plan for potential cancellations or delays if island hopping is on your list. Scuba diving conditions deteriorate significantly, with reduced visibility and stronger currents. On the mainland, Kbal Chhay Waterfall reaches its most dramatic flow during the monsoon, making it worth the bumpy ride inland if you catch a dry morning.
Despite the challenging weather, July and June rank as the busiest months for tourism, which pushes accommodation prices higher than usual. If you do visit during this window, spend your rainy afternoons at Phsar Leu Market sampling fresh seafood, trying Khmer dishes like amok or nom banh chok from the food stalls, or joining a Khmer cooking class. Bring a quality rain jacket and waterproof bags for your electronics.
Fall in Sihanoukville City Centre, Cambodia
September is the wettest month in Sihanoukville, with a 63% chance of significant rain on any given day. Expect heavy afternoon storms, sometimes lasting into the evening, and roads near the coast can flood after sustained downpours. Highs hold steady at 87°F (30.6°C) while lows settle at 77°F (25°C), and the humidity peaks at 82.5% in September before slowly easing. Winds pick up compared to the dry season, with gusts reaching moderate strength, adding chop to the water that continues to limit ferry reliability to the islands.
October brings improvement. Rain chances drop to 48%, and the seas begin to calm enough for occasional island trips. By November, Sihanoukville starts feeling the approach of the dry season: precipitation falls to 34%, humidity drops to 73%, and the air feels noticeably lighter. This is a smart time to visit if you want the benefits of lower monsoon-season prices with improving weather. The beaches are less crowded, the expat-run Saturday market at Otres comes alive with food stalls and live music, and you'll find the city's coastal character more relaxed than during peak season.
Tourism volume remains the second highest of the year across this stretch, partly driven by visitors taking advantage of the seasonal shift. Pack quick-dry clothing for September and October, and a light rain shell for November evenings when the breeze off the Gulf can feel refreshing after the long humid months.
Winter in Sihanoukville City Centre, Cambodia
December through February is Sihanoukville at its best. The monsoon has fully retreated, skies clear to brilliant blue, and the Gulf of Thailand smooths out into warm, inviting turquoise. Highs average 87.6°F (30.9°C), still tropical, but lows dip to 74.5°F (23.6°C), the coolest overnight temperatures you'll find here. January's humidity drops to 64.7%, the lowest of the year, making the heat far more bearable than any other season.
Rain is nearly absent: January sees just a 4% chance of significant precipitation and February only 6%. These are ideal conditions for every water-based activity Sihanoukville offers. Ferries to Koh Rong run reliably, visibility for snorkeling and scuba diving around the offshore islands peaks, and kayaking along the coast or through the mangroves of Ream National Park is uninterrupted by storms. The calm water also means you can comfortably take day trips to quieter islands like Koh Russei (Bamboo Island) or Koh Ta Kiev for a taste of near-empty white sand beaches.
Surprisingly, this is also the slowest tourism season by the numbers, with February recording the lowest visitor volumes of the entire year. That translates to elbow room on Ochheuteal and Otres beaches, shorter waits at beachside restaurants grilling fresh crab and prawns, and a more laid-back atmosphere throughout the city. Bring sunscreen, a wide-brimmed hat, and a light layer for evenings when the sea breeze takes the edge off the warmth.
At a Glance
Monthly weather, visitor crowds, air quality, holidays, and daylight hours to help you plan your trip.
Travel Tips & Safety for Sihanoukville City Centre, Cambodia
Getting around Sihanoukville is easiest by tuk-tuk or ride-hailing apps like Grab, which eliminate the need to negotiate fares. Ferries to Koh Rong and Koh Rong Samloem depart from the pier near Serendipity Beach, with multiple companies running several daily trips during the dry season. Cambodia operates largely on US dollars, so there's little need to exchange currency; you'll receive small change in Cambodian riels. Tipping isn't customary but is appreciated in tourist-facing restaurants and for tuk-tuk drivers.
Petty theft, particularly bag snatching from motorbikes, is the most common safety concern. Keep valuables in a front-facing bag when walking along busy beach roads, especially after dark. Stick to bottled or filtered water, and be cautious with ice at smaller street stalls. The sun is intense year-round at this latitude, so reapply sunscreen frequently and stay hydrated, particularly if you're spending full days on the beach or islands.