If you’re thinking about visiting Siem Reap in the summer, get ready for hot, humid, and wet weather. Daytime highs usually hit 31–33°C (87–92°F), and nights barely cool off, staying above 25–26°C (77–79°F).
With humidity hanging in the air, the heat feels even more intense. You’ll probably notice the air feels heavy, no matter if it’s day or night.
Rain shapes the whole summer vibe here. Showers come often and can be heavy, usually rolling in during the afternoon or evening.
The sky tends to stay overcast, so you won’t get many clear, sunny days. Still, there’s enough daylight to check out temples, wander markets, or explore the countryside between storms.
Winds stay light, so you won’t get much relief from the sticky weather. The mix of heat, humidity, and rain really impacts how you plan your time.
It helps to know what’s coming, so you can pack the right clothes, time your sightseeing, and still enjoy your trip—even in the thick of the wet season.
Overview of Siem Reap’s Summer Climate
In Siem Reap, summer means warm temperatures, high humidity, and lots of rain. You’ll experience a tropical wet and dry climate, with steady heat and long stretches of cloudy skies.
Daily life here really follows the rhythm of the rainy season.
Location and Climate Classification
You’ll find Siem Reap in northwestern Cambodia, about 190 miles from Phnom Penh. The city sits only about 60 feet above sea level, surrounded by flat farmland.
Its climate falls under the tropical wet and dry (Aw) category in the Köppen system. That means you get two main seasons: a dry one with less rain, and a wet one with frequent showers and storms.
Temperatures stay warm all year, with an average of about 29°C (84°F). In summer, highs usually fall between 87°F and 92°F, and lows hover around 77°F to 82°F.
Because the dew points are so high, muggy nights are the norm. You’ll feel that stickiness almost every day, especially once the sun goes down.
Humidity levels push close to 100% during the wettest months, making the air feel even heavier. That constant warmth and moisture is just part of life in Siem Reap.
Seasonal Weather Patterns
Summer brings a mix of heavy rainfall, thick cloud cover, and a bit less daylight. Rain picks up from about 5.7 inches in June to nearly 8.5 inches by August.
By early September, the odds of a rainy day climb over 70%. Thunderstorms show up a lot in the afternoon and evening, while mornings usually start off humid but calm.
Clouds are pretty much always around, with overcast or mostly cloudy skies more than 90% of the time. Sunshine is scarce, and when you add in the humidity, it can feel a bit overwhelming.
Winds barely pick up, averaging just 6 mph, usually from the west. That doesn’t help much with cooling down, so most days feel sticky and still.
Comparison with Other Regions in Cambodia
If you compare Siem Reap to Phnom Penh or coastal spots like Sihanoukville, you’ll find it’s a bit cooler but definitely more humid here. Being inland means you miss out on those sea breezes from the Gulf of Thailand, so rain feels heavier and the air thicker.
Up in the northeast, places like Ratanakiri have more temperature swings because they’re higher up. Nights can get cooler there, while Siem Reap stays warm, even after dark.
Rainfall in Siem Reap is similar to Battambang, but not as intense as the coastal provinces, where monsoon storms really let loose. Still, with all the clouds, Siem Reap feels wetter and more overcast than lots of other inland areas.
This steady heat, high humidity, and heavy summer rain really define the local climate and set Siem Reap apart from other Cambodian destinations.
Typical Temperature Range During Summer
The summer heat in Siem Reap sticks around, with daytime highs in the low 30s °C and warm nights. You won’t get much of a break from the heat—both highs and lows stay in a tight range.
Average High and Low Temperatures
Most summer days, Siem Reap’s highs sit between 31°C and 33°C (87°F–92°F). It’s rare for temperatures to drop below 29°C or jump above 36°C.
At night, lows average about 25°C to 27°C (77°F–81°F). Even after dark, it stays warm and muggy, which is just typical for a tropical climate.
With such a small gap between day and night temperatures, you’ll feel that constant heat all day. Humidity makes it feel even warmer, so evenings can seem almost as hot as the afternoons.
If you’re traveling, you’ll want to pack light clothes and make sure you have access to shade or air conditioning.
Monthly Temperature Variations
Summer runs from June to August, and temperatures don’t change much during these months. The average high drops a bit, from about 33°C in June to 31°C in August.
Nighttime lows stay steady, right around 26°C. This barely-there change comes from the monsoon, which brings lots of clouds and rain.
The hottest stretch usually happens in early June, before the rain really kicks in. By late August, clouds and rain cool things off a bit, but humidity stays high.
So, you don’t get wild temperature swings—just persistent warmth.
Record Extremes and Notable Trends
While summer temps are pretty steady, Siem Reap sometimes hits 36°C or higher on really hot days. On the cooler side, summer nights almost never fall below 25°C.
Records show that the hottest part of the year is usually April, right before the wet season. Summer months are a touch cooler, but the humidity makes up for it.
You’ll notice that the temperature range is narrow, with barely any difference between day and night. That’s just how the tropical wet climate works—warmth and moisture all the time.
Rainfall and Humidity in the Summer Months
Heavy rain, frequent storms, and rising humidity define Siem Reap’s summer. These weather patterns shape daily routines, travel plans, and how comfortable you feel outside.
Average Rainfall Levels
Rain really ramps up as summer gets going. From June through August, expect monthly totals between 150 mm and 250 mm.
By September, some years see rainfall topping 300 mm.
Rain usually comes in short, intense bursts, not long steady showers. Most storms hit in the afternoon or evening and last an hour or two.
That means you can often get out and about earlier in the day, but you’ll want to be ready for sudden downpours.
Compared to the dry season, summer rain is on another level. All this water is crucial for farming, especially rice fields, and it helps refill local water sources.
For visitors, it’s smart to carry rain gear and plan for indoor activities on stormy afternoons.
Number of Rainy Days
You won’t get rain every hour, but wet days are common. On average, 15 to 20 days per month see measurable rainfall in June, July, and August.
September usually brings even more, with 20 or more rainy days.
Most rainy days start clear, with heavy rain showing up later. If you plan your outdoor time for the morning, you might dodge the worst of it.
Rainy days also make rivers rise and rural roads tricky. Flooding can happen in low spots, and dirt roads might turn muddy or hard to cross.
If you’re heading out of the city, plan for possible delays.
Humidity Patterns
Humidity climbs as the summer rains arrive. Relative humidity averages 70% to 80%, and September can push it up to about 75% or higher.
That makes the air feel warmer than it really is.
High humidity also keeps nights from cooling down. Even after sunset, temps often stay above 26°C (79°F), which can get uncomfortable without air conditioning.
Expect sticky conditions, especially when daytime highs hit 32–34°C (90–93°F).
Humidity feels a bit less intense in the mornings, when breezes help out. By midday, the combo of heat and moisture can get pretty intense.
Drink plenty of water and stick to light clothing to handle the tropical climate.
Sunshine, Cloud Cover, and Daylight Hours
Summer in Siem Reap means lots of clouds, not much sunshine, and slightly shorter days as the season goes on. These patterns really affect how much direct sunlight you’ll get and can change your outdoor plans.
Typical Sunshine Duration
You’ll get fewer hours of bright sunshine in summer than during the dry season. Thanks to heavy cloud cover and the monsoon rains, direct sunlight is rare.
Most days, sunshine comes in short bursts between clouds and showers.
During the rainiest weeks, you might only get a couple hours of sun each day. That’s way less than the 7–9 hours you’d see in the dry season.
Even when the sun does peek out, it often looks hazy.
If you want to do things outside, aim for earlier in the day—those are your best chances for some sun. Less sunshine also means midday never feels quite as harsh as the dry season, though the humidity still packs a punch.
Cloudiness and Overcast Days
Clouds rule the summer sky in Siem Reap. The sky is overcast or mostly cloudy about 90% of the time, so clear skies are pretty rare.
The cloudiest days hit in late August, when overcast conditions peak.
Even when it’s not raining, the sky often stays gray. The landscape looks softer and less bright compared to the dry months.
If you’re into photography, you might actually like the diffused light—it’s great for capturing details of temples and scenery.
Daylight Variations Through Summer
Daylight hours slowly shrink as summer goes on. In June, the longest days last about 12 hours and 55 minutes.
By late August, that drops to about 12 hours and 23 minutes.
Sunrise shifts from around 5:36 AM in early June to about 5:53 AM by the end of August. Sunset moves earlier too, from roughly 6:35 PM in July to 6:16 PM in late August.
These changes are slow, so you probably won’t notice much week to week. Still, if you’re planning evening activities, keep in mind that daylight fades a bit earlier as the season moves forward.
Wind Speed and Weather Events
Siem Reap’s summer brings steady but not extreme winds, with some shifts between early and late season. Heavy rain and clouds dominate, but wind speed still affects comfort and travel.
Average Wind Speed by Month
During summer, wind speeds in Siem Reap stay pretty moderate. From June through August, you’ll see averages between 6–7 mph (about 2.5–3 m/s).
That’s just enough for a light breeze—nothing that’ll mess up your plans.
The breeziest stretch usually runs from late May through early September. June and July are the windiest, then things calm down in August.
By September, winds drop closer to 5 mph, signaling the start of quieter months.
Winds here follow the southwest monsoon. This pattern pushes moist air inland, adding to the rain and humidity.
The wind itself isn’t harsh, but it plays a big part in shaping Siem Reap’s summer weather.
| Month | Avg Wind Speed (mph) | Conditions |
|---|---|---|
| June | ~6.5 | Breezy, humid |
| July | ~6.5–7 | Peak summer winds |
| August | ~6 | Gradual decline |
| Sept | ~5 | Calmer, transitional |
Frequency of Windy Days
You’ll notice a steady number of breezy days in summer, but not many strong wind events. Most days bring light to moderate air movement, which takes the edge off the heat but doesn’t get anywhere near damaging.
The windiest stretch lasts about three months. During these weeks, daily wind averages often go above 5.5 mph, so you’ll feel gentle to moderate breezes pretty much every day.
These breezes show up consistently, not just in random bursts, so wind is a regular part of the summer. High-intensity gusts are rare, though.
Siem Reap doesn’t get tropical storms or cyclones in summer, unlike coastal areas. Instead, heavy rain showers and thunderstorms are the main weather events.
Winds might pick up briefly when storms roll in, but they usually calm down once the rain moves on.
Impact of Wind on Daily Life
If you’re traveling or living in Siem Reap, you’ll notice summer winds have some practical effects. The breeze can make hot afternoons feel a bit kinder, especially when the humidity cranks up.
It also helps keep crowded spots from feeling too stuffy, so comfort improves a bit.
Outdoor activities like cycling, temple visits, and river walks usually go on without much fuss. Occasionally, you might feel stronger gusts during a storm, but these don’t last long.
Rain, not wind, tends to mess with daily plans more.
Local transport—tuk-tuks, motorbikes, all that—runs like usual in these wind conditions. Roads can get slippery from rain, but wind almost never interrupts travel.
If you’re heading out to rural areas, those light breezes are actually a bonus. They keep insects away and help cool things off.
Seasonal Weather Impact on Travel and Activities
Siem Reap’s tropical climate brings hot temperatures, high humidity, and seasonal rains, all of which shape how you plan your trip. Heat, rainfall, and comfort change through the year, and they affect what you can do outside and how you prepare.
Comfort Levels and Best Times to Visit
Siem Reap stays warm all year, with daily highs usually between 87°F and 95°F. The hottest stretch is March through May, with April often topping out around 95°F. Humidity runs high, which makes the heat feel even more intense.
From November to February, things get cooler and drier. Daytime highs land closer to 85°F, and evenings can drop to about 70°F, which makes sightseeing way easier.
If you’d rather avoid crowds and don’t mind a bit of rain, try visiting in May or June. Showers happen often but usually don’t last long, and the scenery gets a lot greener.
If you’re sensitive to heat and humidity, the dry season is a better pick for long days exploring the temples.
Outdoor Activities and Precautions
When you visit temples like Angkor Wat in summer, you need to plan ahead. The midday heat ramps up fast, so it’s best to start early in the morning or wait until later in the afternoon.
Bring water, wear light clothes, and don’t forget sun protection.
During the wet season, heavy rains can turn rural roads muddy and slippery. Trips to floating villages or the countryside might take longer, and boat rides can get delayed.
Try to keep your schedule flexible so you can adjust if a sudden storm rolls in.
The rain does have its upsides—it cools the air and clears out dust, making for better photos. If you want to cycle or walk around temple sites, waterproof gear and sturdy shoes will make your day a lot easier.
Travel Tips for Summer Weather
Think about the climate before you pack. Toss in some breathable fabrics, a wide-brim hat, and reliable footwear—those temple grounds can get pretty uneven.
Don’t forget a small umbrella or a light rain jacket, especially if you’re visiting from May to October. That’s when sudden downpours like to surprise everyone.
Try to plan your rest breaks indoors during the hottest part of the day, usually between 11 AM and 3 PM. Most people use that time for lunch or to cool off in museums with decent air conditioning.
Keep in mind, humidity climbs pretty high, so stash your electronics and documents in waterproof cases.
It’s easy to forget, but staying hydrated matters a lot—always keep bottled water handy.