Best Time to Visit Phnom Penh: Heat, Rain and the Water Festival

November to February. Dry, with mornings that are actually pleasant and evenings you can spend outside, which matters more in Phnom Penh than in Siem Reap because this is a city you see on foot and from a tuk-tuk rather than inside a temple complex.

The city is hotter and more humid than most visitors expect, and it does not have Siem Reap's option of retreating to a hotel pool between temples. A day here is markets, a palace courtyard, a walk along the river - all of it outdoors, most of it unshaded.

November is the standout month, and not only for the weather. Bon Om Touk, the water festival marking the reversal of the Tonle Sap river, falls in November and is the biggest event in the Cambodian calendar. Boat racing teams come from across the country, the riverfront fills, and the city is busier and better than at any other time of year. It is also completely booked out, so plan months ahead or plan around it.

The flip side: April. High thirties, heavy humidity ahead of the rains, and a city that becomes genuinely hard work between eleven and four.

November - the best month. Rains finished, humidity dropping, the river high, and the water festival. Book early.

December - January - the coolest and driest stretch, with mornings in the mid-twenties. Peak season prices, though Phnom Penh never gets Siem Reap's crush.

February - still dry and comfortable, warming through the month.

March - heat building. Mornings fine, afternoons increasingly not.

April - the hardest month. High thirties, thick humidity, and Khmer New Year around 13-16 April, which is a genuine national shutdown. Much of Phnom Penh empties as people return to their home provinces; a lot of businesses and some museums close, and the city is unusually quiet in a way that is either lovely or inconvenient depending on your plans. Water-throwing is part of it and you will not stay dry.

May - June - the rains establish. Hot, humid, with heavy afternoon storms that can flood streets quickly and briefly. Prices fall.

July - August - proper wet season, usually one heavy hour rather than all-day rain. The city is green, the river is rising, and hotels are cheap.

September - October - the wettest weeks and the lowest prices. Pchum Ben, the ancestor festival, falls in September or October and is a solemn public holiday when pagodas are crowded and many businesses close for several days. Worth seeing; worth checking the dates.

Shape the day around the middle of it. Out early for the markets - the food trade is done by nine anyway - then the palace and the museum in the cool of the morning, indoors or asleep from twelve to three, and back out from four. This is not laziness; it is how the city itself works.

The rain is short and sharp, not a drizzle. From May to October the afternoon storm arrives fast, drops a lot of water, floods some streets for half an hour and then stops. A light poncho beats an umbrella because the wind comes with it, and tuk-tuks have roll-down sides that work better than you would expect.

Dress for the palace, not for the weather. The Royal Palace enforces shoulders and knees at the gate, for everyone, whatever the temperature. Light long trousers and a sleeved shirt are the answer and are better in the sun anyway.

Mosquitoes are worth taking seriously, particularly at dusk and in the rainy months. Dengue is present in Cambodia and Phnom Penh is an urban dengue environment; repellent and covered ankles in the evening are the sensible minimum.

Flooding during heavy rain affects some streets more than others, and a tuk-tuk will simply refuse a flooded road. Build slack into anything time-critical in the wet season.

Phnom Penh is cheaper than Siem Reap for equivalent quality and much less seasonal, because it is a working capital rather than a tourism town. The swing is real but nothing like the temple economy up north.

Peak (December - January, plus water festival week in November): rates up meaningfully, and the water festival week is genuinely full. Book ahead for that one specifically.

High (November, February): comfortable weather, good availability.

Shoulder (March, October): softening prices, workable conditions.

Low (May - September): 30-40% below peak, and good hotels become very good value.

What things cost: guesthouse double USD 15-30; a good hotel with a pool USD 40-80; the riverside and BKK1 boutiques USD 100 and up. A tuk-tuk across town is a couple of dollars, a half-day city tour USD 45-65, and a private full-day car with guide USD 130-200. Street food USD 1.50-3 a plate.

Festivals worth knowing about: Bon Om Touk in November, the water festival and the best thing in the city's year; Khmer New Year in mid-April, when the city empties and closes; Pchum Ben in September or October, a solemn ancestor festival and a multi-day public holiday.

If you are planning dates across a whole trip rather than one city, our Cambodia itineraries set out honestly what each trip length reaches, and the 2-day Phnom Penh itinerary shows what the city itself needs.