★★★
Budget
Phnom Penh Infinity Pool Down to $25/N - M Residence
From $43 / night
Check Prices on Trip.com →
Things to Do in Phnompenh in September
September weather, activities, events & insider tips
Low Season · Budget Friendly
September Weather in Phnompenh
Temperature, rainfall and humidity at a glance
89°F (32°C)
High Temp
75°F (24°C)
Low Temp
10.7 inches (272 mm)
Rainfall
70%
Humidity
⚠ Heavy monsoon downpours flood low-lying streets quickly. Avoid wading through standing water. Uncovered drains and potholes lurk beneath. Skip motorbike rentals on slick, flooded roads. The risk is real. Stay dry. Stay safe.
⚠ High, fast-moving river levels at the Mekong-Tonlé Sap-Bassac confluence demand caution. Use only licensed boat operators. Life jackets are non-negotiable. Some river trips may be scaled back or canceled after storms. Check schedules daily. Flexibility saves the day.
Is September Right for You?
Weigh the advantages and considerations before booking
Advantages
- + September is the cheapest, quietest stretch for Phnom Penh. Green season rules, so riverfront guesthouses along Sisowath Quay and the boutique places off Street 240 slash their dry-season rates. Walk straight into the Royal Palace or the National Museum mid-morning. No tour-group shuffle.
- + The rivers hit peak drama now. By September the Tonlé Sap has reversed, swelling the Chaktomuk confluence where the Mekong, Tonlé Sap and Bassac collide. Brown water races high past the promenade. Late afternoon light turns copper. Rain clears. The riverfront is the best free show in town.
- + Rain keeps a schedule you can plan around. Downpours build in the afternoon. They fall in heavy 30-to-60-minute bursts, not all-day soakers. You still get bright, cool mornings. Expect 24°C / 75°F at dawn. Good for outdoor sightseeing.
- + You arrive as the country enters its most meaningful season. The 15-day Kan Ben observances leading up to Pchum Ben usually begin in late September. Pagodas, Wat Botum, Wat Ounalom, Wat Phnom, fill before dawn with white-clad families carrying offerings. You see Cambodian life as it is, not as it's packaged.
Considerations
- − The rain is heavy this month, about 10.7 inches (272 mm) across roughly 10 days. Phnom Penh's drainage stumbles. Low-lying streets, parts of the Russian Market area and stretches near Koh Pich can flood ankle- to shin-deep within twenty minutes. Traffic seizes up until the water drains.
- − Humidity hovers around 70%. The heat index makes 32°C (89°F) feel heavier than the number suggests. Walking the open, shadeless plazas around Independence Monument or the Royal Palace forecourt at midday is sweaty, draining work. The sun is still strong. UV index 8. You can burn through the haze.
- − Day-trips tied to the Mekong and the roads out of town turn less reliable. River levels run high and fast. Some boat operators scale back. Unpaved approaches to spots like Koh Dach (Silk Island) can turn to mud after a storm. Keep plans flexible. Allow slack.
Best Activities in September
Top things to do during your visit
Royal Palace and Silver Pagoda Guided Walks
September's thin crowds let you tackle the Royal Palace properly. The Throne Hall's gold spire gleams against bruised monsoon skies. The Silver Pagoda, its floor laid with thousands of solid silver tiles, feels almost private. Arrive at opening. The compound shuts over lunch. Afternoon rain arrives as heat peaks. Start at 7:30-8am. Cool air, soft light, room to breathe.
Booking Tip: Walk-in entry is easy in low season. A licensed guide flips the complex from pretty buildings into a living story. Book a reputable, registered guide 1-3 days ahead. Confirm coverage of both the Palace and the National Museum. Dress code is strict: shoulders and knees covered. Lay out clothing the night before. See current guided options in the booking section below.
Mekong and Tonlé Sap Sunset River Cruises
September is when a river cruise stops being gimmick and starts making sense. The rivers are full, fast and dramatic at the Chaktomuk confluence. A late-afternoon boat times the gap well. Push off after the downpour clears the air. Watch the city's silhouette and the Royal Palace light up gold. Feel a breeze for the first time all day. High water sets boats level with the promenade.
Booking Tip: Book a sunset slot roughly two hours before dusk. Reserve 1-2 days ahead. Pick a licensed operator with covered seating and visible life jackets. Storms can blow up fast this month. Ask if they sail in rain. Good crews wait out squalls. Check current departures in the booking widget below.
Phnom Penh Street Food and Market Tours
Rainy season equals comfort-food season. September is prime for a guided eating walk. Wet weather pushes you under tarps and into covered markets. You smell charcoal and lemongrass before you see the cart. Taste bai sach chrouk (grilled pork over broken rice) and a sour, herby bowl of kuy teav. Duck into the 1937 art-deco rotunda of Phsar Thmei (Central Market) when the sky opens. Vendors are relaxed. Few visitors around.
Booking Tip: Evening tours work best in September. You dodge midday heat and catch the markets at their liveliest. Book 2-5 days ahead. Choose a guide who partners with hygienic, long-established stalls. Wear sandals you don't mind soaking. Browse current food-tour options in the booking section below.
Tuol Sleng and Choeung Ek History Tours
These two sites, the S-21 prison museum and the Choeung Ek memorial, are the most important stops in Phnom Penh. They are also the most weather-proof. Tuol Sleng's former classrooms are largely indoors. The audio-guided walk at Choeung Ek works in drizzle or blazing sun. September's quieter galleries grant space and silence. No shuffling through crowds.
Booking Tip: Pair both in a single half-day with a licensed driver-guide. Start at Tuol Sleng in the morning before afternoon rain. Bring the audio guide at Choeung Ek. It turns a field into understanding. Reserve a guide 1-2 days ahead. See current combined tours in the booking widget below.
Koh Dach (Silk Island) Cycling and Weaving Visits
A short ferry hop from the city lands you on Koh Dach, a green river island of stilt houses and home looms. Families have woven Cambodian silk here for generations. September's high Mekong makes the crossing scenic and the island lush. Loom workshops stay blessedly dry when showers pass. Twenty minutes from downtown traffic to the clack of wooden looms and the smell of wet earth. The contrast is the whole point.
Booking Tip: Arrive early, before storms churn the island's lanes into soup, and insist on a tour that boards the local ferry instead of a private speedboat. The crossing feels real. Reserve 2-4 days ahead and double-check they sail even through light rain. Current island tours sit in the booking section below.
Pchum Ben Pagoda and Temple Visits
Late September hands you the lead-up to Pchum Ben, Cambodia's soulful festival of the ancestors, and it costs nothing. Before sunrise, families in white glide into Wat Botum, Wat Ounalom and Wat Phnom cradling bai ben, sticky rice balls dotted with sesame for the dead. Incense and frangipani hang thick air. Monks chant low, steady waves. The city slows, reverent.
Booking Tip: This is quiet watching, not a ticketed show. Speak softly. Dress modestly in light or white. Photograph only with clear permission. Let a local guide decode the ritual so you grasp what develops. Mornings rule. Guided cultural walks wait in the booking section below.
Where to Stay in Phnompenh in September
Hand-picked hotels across price tiers for September travellers.
September Events & Festivals
What's happening during your visit
Late September
Kan Ben (lead-up to Pchum Ben)
Pchum Ben ranks among Cambodia's weightiest religious festivals, saluting ancestors across 15 days known as Kan Ben. Late September usually opens the cycle, climaxing in early October. Phnom Penh's pagodas swell before dawn as families bear food and bai ben for monks to dedicate to the departed. To witness it, reach Wat Botum or Wat Ounalom at first light, dress modestly, and observe in silence. No museum equals the view into Khmer spiritual life.
Packing Checklist
Bookmark this page — your progress is saved between visits
Need the full list with shopping links?
Climate-specific gear, brand recommendations, and what to leave at home.
View Phnompenh Packing List →Essential Tips
Insider knowledge and common pitfalls to avoid
Insider Knowledge
Treat afternoons as flexible. Locals run errands and sightsee in the morning. From 2pm to 5pm they shelter indoors while the sky unloads. Schedule a long lunch or a museum then and you won't care about the storms.
Use the rain as use. September is low season. Room rates along Sisowath Quay and around Street 240 dip. Ask politely for a better nightly rate when you book direct or stay several nights. It works.
When streets flood, don't wade blind. Phnom Penh's drains lose covers and the water hides holes and high curbs. Wait fifteen minutes over iced coffee. The flood drains as fast as it rose.
If your trip lands during Kan Ben before Pchum Ben in late September, reach a pagoda at dawn, not mid-morning. The dawn offerings are the soul of the ritual. The air is cool. You beat the heat and the crowds.
Avoid These Mistakes
Don't assume September rain equals ruined days and cram indoor backups. Mornings are often clear and lovely. Front-load outdoor plans before noon and you'll accomplish more than hiding inside all day.
Skip renting a motorbike to zip around the city or out to Koh Dach in wet season. Flooded streets, slick asphalt and chaotic traffic spell danger. A metered tuk-tuk via a ride app is cheaper on nerves and safer.
Never show up at the Royal Palace or a pagoda in a tank top and shorts. Guards will turn you away. Covered shoulders and knees are mandatory. During Pchum Ben, modest dress is more than a rule; it's respect.
Explore More Activities in Phnompenh
Didn't see anything interesting yet?
Browse Viator's full catalog of tours, day trips, food experiences, and private guides in Phnompenh.
See All Phnompenh Tours on Viator