When you picture summer in Phnom Penh, get ready for hot, humid, and wet days that really define life in Cambodia’s capital.
Average daytime highs usually sit in the upper 80s to mid-90s Fahrenheit, while nights stay warm and muggy, hovering around the upper 70s.
The heat teams up with almost constant humidity, making the air feel heavy and tropical.
Clouds cover the sky for much of the season, and rain grows more frequent as summer rolls on.
Showers arrive in bursts—sometimes heavy, usually short—leaving behind damp streets and that lush, green look everywhere.
You’ll also notice the days get a bit shorter from late June through August, but there’s still plenty of daylight for exploring.
If you’re planning a trip during these months, it helps to know how the weather changes from month to month.
Understanding temperature trends, rainfall patterns, and the way the city adapts gives you a real sense of what summer feels like here.
Overview of Phnom Penh’s Summer Climate
Summer in Phnom Penh means hot temps, high humidity, and lots of rain.
The tropical monsoon climate shapes the season, bringing plenty of clouds and wet weather.
While it’s warm all year, summer stands out for its heavy rains and muggy air.
Geographic and Climatic Context
Phnom Penh sits in southern Cambodia, right along the Mekong and Tonlé Sap rivers.
Its low elevation and flat landscape put it right in the path of the tropical monsoon system.
The city falls under the tropical monsoon (Am) category in the Köppen system.
This climate brings clear wet and dry seasons, but not big swings in temperature.
You’ll feel average highs between 89°F and 94°F (32–34°C) in summer, and lows stick around 77–82°F (25–28°C).
Humidity stays high, often close to 100% for much of the season, so the air feels even warmer than the thermometer says.
Because rivers and floodplains surround the city, heavy rain can quickly push up water levels.
This raises the risk of flooding, especially in low-lying areas.
Seasonal Patterns in Cambodia
Summer in Phnom Penh usually runs from June through August, lining up with the southwest monsoon.
Rain shows up often, with the chance of a wet day climbing from about 50% in June to over 60% by late August.
Rainfall averages 5 to 7 inches per month, usually coming in short, intense downpours.
These storms tend to hit in the afternoon or evening, so mornings are often pretty dry.
Clouds stick around, and skies are overcast or mostly cloudy about 90% of the time.
Sunshine is limited, but you’ll still get about 12–13 hours of daylight each day.
Winds shift with the monsoon, blowing mostly from the west and southwest.
Average wind speeds stay light to moderate, around 7 mph, which helps a bit with the heat.
Comparison to Other Seasons
Compared to spring, summer feels wetter and cloudier, though temperatures don’t change much.
Spring usually brings the year’s hottest days, but summer’s rain cools things off a little in the afternoons.
Autumn, from September to November, keeps the rain going, but it gradually lets up by late season.
Temperatures stay warm, but the air isn’t as stifling as in peak summer.
Winter, from December to February, brings the driest and most comfortable weather.
Rain hardly shows up, skies clear up, and humidity drops.
Daily highs hover around 86–89°F (30–32°C), making it a much better time for outdoor fun than the muggy summer.
Monthly Temperature Trends
Phnom Penh’s summer climate stays hot and humid, with only minor shifts in temperature each month.
Daytime highs, nighttime lows, and seasonal differences are subtle, but they still affect how you feel outside.
Typical Daytime and Nighttime Temperatures
During summer, daytime highs usually land between 89°F and 94°F (32°C to 34°C).
Temperatures rarely dip below 86°F or climb above 99°F, so the heat is pretty steady.
Nights are warm, averaging around 79°F (26°C).
You won’t get much cooling after sunset, so muggy nights are the norm.
Air conditioning or a good fan becomes your best friend for sleeping.
The difference between day and night temperatures is small, usually just 10–12°F.
That makes the heat feel relentless, since nights don’t offer much relief.
Hottest and Coolest Summer Months
June often kicks off with the highest temperatures, with daily highs near 94°F (34°C).
The heat is strong, and as the month goes on, rain adds even more humidity.
By July and August, highs drop a bit to around 89°F to 91°F (32°C to 33°C).
It’s not a huge difference, but you might notice fewer scorchers compared to early summer.
Even at its coolest, summer days rarely dip below the upper 80s.
Nights stay steady in the upper 70s, so it’s warm across all three months.
| Month | Avg High °F | Avg Low °F |
|---|---|---|
| June | 94 | 79 |
| July | 91 | 79 |
| August | 89 | 79 |
Year-to-Year Variability
Summer temperatures in Phnom Penh don’t swing wildly from year to year.
You won’t see big jumps like in temperate places, but some summers might run a tad hotter, with more days above 95°F.
Others might feel milder if there’s more cloud cover and rain.
These small changes usually follow regional weather patterns, like shifts in the monsoon’s strength.
Since the climate stays tropical, you can count on hot, humid weather every summer.
Rainfall changes more from year to year, but temperatures stick close to the long-term average.
Rainfall and Humidity During Summer
In Phnom Penh, summer kicks off the wet season, bringing frequent showers and high humidity.
Rain picks up steadily through the months, and humidity stays high, shaping your daily experience.
Rainy Season Onset and Duration
The rainy season in Phnom Penh usually starts in May and runs until November.
The heaviest rain falls from September to October.
Summer months—June, July, and August—sit right in the middle, so rain is almost a daily thing.
You’ll get frequent, short, but intense showers, mostly in the afternoon or evening.
Storms clear out quickly, but leave things damp.
The Southwest Monsoon brings moisture from the Indian Ocean, which really shifts the weather compared to the drier months earlier in the year.
If you’re visiting, expect wet streets, occasional flooding in low-lying areas, and more clouds overhead.
Despite all the rain, mornings often stay dry, so it’s a good time for outdoor plans before storms build up later.
Monthly Precipitation Levels
Rainfall in Phnom Penh during summer is no joke.
On average:
| Month | Rainfall (mm) | Rainy Days |
|---|---|---|
| June | ~180–200 mm | 15–17 days |
| July | ~220–230 mm | 17–18 days |
| August | ~230–240 mm | 18–19 days |
September usually sees the most rain, with about 250 mm across 19 days, but the buildup starts in June.
Rain falls in bursts, not all day, so you might get a heavy downpour followed by clear skies.
Streets can flood fast during peak showers, but water usually drains away in a few hours.
Since rain spreads over so many days, you’ll want to plan for wet weather as part of your daily routine.
Carrying light rain gear makes sense if you’re getting around the city.
Humidity Patterns
Humidity in Phnom Penh during summer stays high, often above 80%.
It peaks in September, with average relative humidity around 84%.
The lowest levels show up in February, dropping to about 71%.
High humidity plus temps near 30–33°C makes the air feel even warmer.
You’ll probably notice it feels uncomfortable during midday, when both heat and moisture are at their highest.
Morning humidity is a bit lower, so the early hours are better for being outside.
By afternoon, humidity rises as rain builds, making the air heavy and damp.
If you’re indoors, fans or air conditioning help a lot.
Outside, staying hydrated and wearing light clothes make things easier.
This thick, moist air is just part of Phnom Penh’s tropical monsoon vibe.
Wind, Sunshine, and Atmospheric Conditions
During summer in Phnom Penh, you get steady winds, lots of cloud cover, and fewer sunshine hours than in the dry season.
Air pressure doesn’t change much, and visibility can drop during heavy rain, but it usually clears up fast once storms move on.
Average Wind Speeds
Winds in Phnom Penh during summer usually stay light to moderate.
Expect average speeds of 6–12 km/h (4–7 mph), mostly from the southwest thanks to the monsoon.
These winds bring in moisture from the Gulf of Thailand, fueling those frequent showers.
Strong gusts don’t show up often, but storms can bring brief bursts that settle down quickly.
For most people, the wind doesn’t mess with daily plans.
Streets stay calm, and you won’t run into dust or sand in the breeze.
Winds actually give a bit of relief from the humidity, especially later in the day.
Hours of Sunshine
Clouds rule Phnom Penh’s summer.
You usually get 4–6 hours of sunshine per day, much less than the 7–8 hours that come with the dry season.
July and August are especially cloudy, with skies overcast or mostly cloudy about 90% of the time.
Still, days brighten up between showers.
Rain often comes in short, heavy bursts, so you’ll get breaks of sunshine afterward.
It’s not unusual to see both bright sun and dark clouds in the same afternoon.
If you want to do things outside, mornings are your best bet for clearer skies.
Keep some light rain gear handy, since sudden showers are pretty common.
Air Pressure and Visibility
Air pressure in Phnom Penh holds steady through summer, averaging around 1005–1008 hPa.
You probably won’t notice much change, but the constant humidity makes the air feel heavy.
Visibility is usually good, often above 8–10 km, but heavy rain can bring it down fast.
Thunderstorms might cut visibility to just a few hundred meters, but things clear up quickly once the rain stops.
Haze isn’t much of an issue in summer, since the frequent rain washes particles out of the air.
The atmosphere feels cleaner, though the high humidity can still blur the horizon a bit.
Travel Considerations for Summer Visits
Visiting Phnom Penh in the summer means you’ll deal with high humidity, frequent rain, and warm temps.
You can still have a great time if you plan around the weather, stay flexible, and pack smart.
Best Times to Visit
Summer in Phnom Penh lines up with the wet season, which runs from May through October.
Rain showers happen often, especially in July and August, but they usually don’t last all day.
If you’re looking for fewer crowds and lower hotel prices, summer’s a solid choice.
But if you want the most comfortable weather for sightseeing, November to March is usually best, since it’s drier and cooler.
During summer, mornings tend to be clearer, so it’s smart to plan outdoor activities like temple visits or riverside walks early.
Afternoons often bring heavier rain, so save indoor stuff—like museums or cafés—for later.
Summer isn’t the peak tourist season, but you’ll enjoy quieter attractions and more open accommodations.
If you don’t mind a bit of rain, it’s a pretty decent trade-off.
Weather-Related Travel Tips
Daytime highs usually hit around 89–94°F (32–34°C), and the humidity? It’s pretty much always close to 100%. You’ll probably notice muggy air both day and night, so it’s tough to escape.
Drink plenty of water and look for shade or air conditioning when you can. That’ll help you handle the heat a bit better.
Summer brings around 5–7 inches of rain each month, with August and September being especially wet. Flooded roads happen fast in the lower parts of Phnom Penh, so you should plan for extra travel time.
Try not to pack your schedule too tightly, since getting stuck in traffic or detours is common when it pours.
Tuk-tuks and taxis usually keep running, even when the weather turns rough. I’d keep a lightweight raincoat or umbrella with you, just in case.
Sudden downpours can mess up walking tours, so it’s smart to keep your plans loose.
Mosquitoes get more active when it rains. Use repellent and wear long sleeves in the evenings, especially if you’re near rivers or parks.
Packing Recommendations
You’ll want lightweight, breathable clothes to stay comfortable in Phnom Penh’s summer heat. Cotton and linen are your friends—they dry fast and let air through.
Skip anything heavy that’ll trap heat and sweat.
Bring rain protection like:
- Compact umbrella
- Waterproof sandals or shoes
- Light rain jacket
Humidity means you’ll probably want extra changes of clothes. Quick-dry travel gear comes in handy if you plan to wash things while you’re there.
Don’t forget insect repellent, sunscreen, and a reusable water bottle for health and safety. Lots of travelers also pack tissues or wipes, since public restrooms don’t always have supplies.
A wide-brimmed hat and sunglasses can help with the morning sun. If you have a small waterproof bag or pouch, that’s great for keeping your electronics safe during those sudden rain bursts.
How Summer Weather Shapes Life in Phnom Penh
High heat, heavy humidity, and frequent rainfall really shape how people live in Phnom Penh. You’ll see it in the way folks work, travel, and even how fast or slow the city moves.
Local Activities and Events
Summer lines up with the wet season in Phnom Penh, so outdoor events have to work around afternoon downpours. Street markets usually open early, when it’s a bit cooler and there’s less chance of rain.
Festivals and cultural gatherings still happen, but organizers often set up tents or covered spaces. Riverside spots stay popular for evening walks, but crowds will thin out fast if the sky starts looking stormy.
Sports like football often move indoors when the rain gets heavy.
Tourism shifts too. Boat rides on the Tonle Sap and Mekong rivers still go on, but weather and water levels can change the schedule.
Museums and temples get busier during the day since people look for shelter from the heat and storms.
If you’re exploring, light rain gear is a must and you’ll need to stay flexible with your plans. Locals hop on motorbikes with ponchos, while most visitors stick to tuk-tuks with rain covers.
Impact on Daily Routines
Humidity in Phnom Penh hovers close to 100% on most summer days. You’ll notice people moving slower in the city during peak heat hours.
Most folks plan errands and outdoor work early in the morning or later in the evening, when it’s not quite so brutal outside. The midday heat just makes everything feel a bit heavier.
Rainfall patterns shape the way people get around. Streets flood fast, so traffic slows down and walking turns into a challenge.
If you ride a motorbike or take the bus, you might want to leave earlier than usual. It’s not uncommon to get stuck waiting out a heavy downpour.
Food habits definitely change. People reach for cold drinks and fresh fruit, and lighter meals just seem to make more sense.
Shops and offices crank up the fans or switch on the air conditioning to make things indoors a little more tolerable.
Still, life keeps moving here. Locals have found all sorts of ways to work around the heat and rain, mixing work, rest, and daily errands so they can get through Phnom Penh’s summer weather.