You’re standing on the Riverside Path in Phnom Penh, a cold sugar cane juice in hand, and suddenly the sky isn't just gray—it’s a deep, bruised purple. Then, the bottom drops out. This is the reality of cambodia weather phnom penh, and honestly, it’s rarely what the glossy brochures tell you. Most travel sites treat the weather here like a binary switch: dry or wet.
But it's way more chaotic than that.
The Two-Season Myth and What Actually Happens
The official line from the Ministry of Water Resources and Meteorology (MOWRAM) is that Cambodia has two seasons. You’ve got the dry season from November to April and the rainy season from May to October. Simple, right?
Not really.
If you visit in April, "dry" feels like a cruel joke. It’s the hottest month of the year. We're talking $35°C$ to $40°C$ ($95°F$ to $104°F$) with humidity so thick you feel like you’re breathing through a warm, damp towel. Then there’s the "cool" dry season in December and January. Recently, in early 2026, we saw temperatures in the highlands drop to $14°C$, which sent everyone in the capital scrambling for jackets they haven't touched in years. In Phnom Penh itself, it hit a crisp $15°C$ or $17°C$ overnight.
It was glorious. But it was short-lived.
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The rainy season is also misunderstood. People think "monsoon" means it rains for 24 hours straight for six months. It doesn't. Usually, you get a beautiful, clear morning, followed by a frantic, sky-is-falling downpour for an hour in the late afternoon. Then the sun comes back out, and the city steams.
Breaking Down the Humidity Factor
Humidity is the real boss of Phnom Penh. While the temperature might say $30°C$ ($86°F$), the "feels like" index—what experts call the heat index—is often $10°C$ higher.
- Dry Season Humidity: Ranges from 50% to 70%.
- Rainy Season Humidity: Often stays above 80%, hitting 90% at night.
Basically, if you’re planning to walk between the Royal Palace and the National Museum in August, you’re going to need a change of clothes. Or a very fast Tuk-Tuk with a good breeze.
The 2026 Shift: Why It’s Getting Hotter
We have to talk about the elephant in the room: the Urban Heat Island effect. Phnom Penh is growing fast. Concrete, asphalt, and a lack of green space in the city center trap heat. A recent UN climate report warned that Phnom Penh is one of the fastest-heating capitals in Southeast Asia.
They're projecting up to 250 days a year where the heat index stays above $35°C$.
If you’re visiting now, you’ll notice the difference between the leafy streets of BKK1 and the concrete jungle of the riverside. The temperature difference can be as much as $2°C$ to $7°C$ just based on how many trees are on the block. This isn't just "weather" anymore; it's a changing urban climate.
Monthly Breakdown: When Should You Actually Go?
If you want the best version of cambodia weather phnom penh, aim for December or January. The sky is a piercing blue, the humidity is at its lowest, and you can actually walk outside at noon without melting.
February is still great, though the dust starts to kick up as things dry out.
By March, the "Heat Season" starts. This is the toughest time for sightseeing. April brings the Khmer New Year, and while the water fights help, the heat is intense.
May to July is the "Green Season." The rains start, the dust settles, and the surrounding countryside turns a vivid, impossible green. This is actually my favorite time to be here. The prices are lower, the crowds are gone, and the afternoon storms are spectacular to watch from a rooftop bar.
September and October are the wettest. This is when you see the Tonle Sap river swelling and the "water reversal" phenomenon, which leads into the massive Bon Om Touk (Water Festival) in November. Just be prepared for some localized flooding on the roads.
Practical Survival Tips for the Capital
Forget the umbrella. In a Phnom Penh monsoon, an umbrella is just a sail that helps the wind knock you over. Get a $1 plastic poncho from a street vendor. They’re ugly, but they work.
Hydration isn't a suggestion here; it's a requirement. If you aren't drinking a liter of water every few hours, the heat will catch up with you. Local experts and long-term expats swear by "electrolyte powder" packets sold in every Pharmacie de la Gare.
Dress for the humidity, not just the heat. Linen and light cotton are your best friends. Avoid synthetic fabrics unless they are specifically moisture-wicking sports gear, or you’ll end up in a self-made sauna.
Actionable Next Steps for Your Trip:
- Check the MOWRAM website or their Facebook page for real-time updates—they are surprisingly accurate for storm warnings.
- Download a "Heat Index" app rather than just a temperature app; it’ll give you a better idea of when to stay indoors.
- Book accommodation with a pool if you’re visiting between March and May. You will thank yourself at 2:00 PM every single day.
- Schedule your "Big Sights" (Royal Palace, Killing Fields) for 8:00 AM. By 11:30 AM, you want to be in a museum with AC or a cafe.
The weather here is a character in its own right—loud, unpredictable, and sometimes overwhelming. But if you stop fighting it and start planning around the rhythm of the sun and the clouds, Phnom Penh is one of the most rewarding cities in Asia.
Keep an eye on the sky, carry your sunscreen, and maybe keep a light sweater in your bag for those surprisingly chilly January nights. It’s a wild ride.