When you plan a trip to Siem Reap in the fall, you’ll find warm days, cooler nights, and a noticeable shift from the rainy season toward drier skies.
Average daytime highs hover near 86°F, and nighttime lows gradually drop from the upper 70s to the low 70s, so the weather feels more comfortable as the season moves along.
Rainfall still makes a mark early in the season, but it eases off quickly as the weeks pass.
September often brings heavy showers, but by late November, rain becomes rare.
This change means you’ll get clearer skies and more sunshine, so you can explore temples and outdoor sites without constant interruptions.
Humidity stays high, but it backs off a bit toward the end of fall, making outdoor activities less stifling than during the peak wet months.
Winds remain steady but light, and daylight hours get shorter, creating a balance between the lush green landscapes left by the rains and the drier, more travel-friendly conditions that follow.
Overview of Siem Reap’s Fall Climate
In the fall months, Siem Reap brings steady warmth, high humidity, and a quick shift from heavy rainfall to drier skies.
The area’s tropical setting, flat terrain, and seasonal wind changes all shape the weather you’ll notice.
Climate Classification and Regional Context
Siem Reap falls under a tropical wet and dry climate (Aw) in the Köppen system.
You get two main seasons here: a long wet season and a shorter dry season.
Fall sits right at the transition, with September still very wet and November much drier.
Average daily highs in fall stick around 86°F (30°C).
Lows range from 79°F (26°C) early in the season to about 73°F (23°C) by late November.
Rainfall drops sharply, from over 8 inches in September to less than 1 inch by the end of November.
Humidity usually stays above 85%, but it gets a little more comfortable as rainfall drops off.
Skies clear up pretty fast, with mostly cloudy days in early fall giving way to more sunshine by late November.
Elevation and Geographic Factors
Siem Reap sits at about 59 feet (18 meters) above sea level.
The terrain is flat, with cropland and artificial surfaces stretching across the landscape.
Since there’s no elevation change, you won’t get cooler mountain air or strong microclimates.
Because the region is low-lying, heat and humidity stay trapped near the surface.
This makes the air feel warmer and muggier than the thermometer suggests.
Winds stay light, averaging about 5 mph, and shift direction as the season changes.
Tonle Sap Lake nearby also shapes the local climate.
Moisture from the lake fuels the wet season rains, and as fall goes on, reduced evaporation helps dry things out.
Comparison to Other Seasons
Compared to spring and summer, fall is less extreme in rainfall but still humid.
Summer months bring the heaviest downpours, while fall marks the retreat of the monsoon.
By late November, the weather starts to feel more like the dry season that peaks in winter.
Temperatures in fall are steadier than in spring, when highs climb toward 95°F (35°C).
Winter is a bit cooler, with average highs around 85°F (29°C) and lower humidity.
Fall lands between these, giving you warm but gradually improving conditions for outdoor activities.
If you visit in fall, you’ll notice the sharp change from wet, overcast skies in September to clearer, drier weather by November.
This seasonal shift makes fall one of the more dynamic times of year in Siem Reap.
Typical Fall Temperatures in Siem Reap
Fall in Siem Reap brings steady warmth with only small shifts between September and November.
You can expect hot afternoons, slightly cooler nights, and a gradual drop in humidity as the season rolls on.
Average Daytime and Nighttime Temperatures
During fall, daytime highs in Siem Reap usually hang around 29°C to 30°C (84°F to 86°F).
The heat stays pretty consistent, and afternoons often feel warm but not extreme compared to the peak summer months.
At night, temperatures cool to about 23°C to 26°C (73°F to 79°F).
This drop makes evenings more comfortable for outdoor activities.
Nights rarely fall below 20°C, so you won’t need heavy clothing.
You’ll notice the difference between day and night, but it’s not dramatic.
Expect warm mornings, hot afternoons, and mild nights throughout the season.
Temperature Trends from September to November
From September through November, daily highs don’t budge much, staying close to 30°C.
The bigger change comes at night, with lows gradually dropping by about 3°C over the season.
In September, nights average near 26°C.
By late November, they dip closer to 23°C.
This shift makes late fall evenings more pleasant for walking or dining outdoors.
Humidity also drops in this stretch, so the same temperatures feel less oppressive as November approaches.
With less cloud cover, the air feels clearer and more comfortable than at the start of the season.
Notable Highs and Lows During Fall
Extreme temperatures rarely show up in Siem Reap during fall.
Highs almost never exceed 33°C (91°F), and lows pretty much stay above 20°C (68°F).
For context, the hottest part of the year hits in April, when highs can reach 35°C or more.
Fall weather is much milder and easier to handle.
The coolest period arrives in January, when lows can drop to about 21°C.
Fall sits comfortably between these two, offering steady warmth without dramatic swings in temperature.
Rainfall and Precipitation Patterns
Siem Reap has a tropical monsoon climate, so rainfall shapes the weather during the fall months.
You’ll see high precipitation totals, frequent rainy days, and a gradual shift toward drier weather as fall moves along.
Monthly Rainfall Totals and Trends
During fall, rainfall in Siem Reap peaks before tapering off toward season’s end.
September is the wettest month, averaging around 280–290 mm of rain.
This heavy rainfall comes with the monsoon’s strongest influence.
October still brings significant rain, usually between 180–220 mm, but totals drop compared to September.
By November, precipitation falls sharply, averaging 50–70 mm, signaling the dry season’s approach.
This downward trend shows just how quickly the climate shifts in a few months.
While temperatures stay steady, the amount of rain you see changes a lot from early to late fall.
| Month | Average Rainfall (mm) |
|---|---|
| September | ~286 mm |
| October | ~200 mm |
| November | ~60 mm |
Frequency of Rainy Days
The number of rainy days matches the monthly rain totals.
In September, you’ll get around 18 days with measurable rainfall.
That makes it the most consistently wet month of the year.
In October, rainy days drop to about 12–14, though showers can still be intense.
By November, rain only falls on about 3–5 days, so you get more chances for outdoor plans.
Rain often falls in short but heavy bursts, especially in the afternoon or evening.
Even in wetter months, you might still find dry periods during the day to explore.
Transition from Wet to Dry Season
The fall months mark the move from wet season to dry season.
In September and early October, weather stays humid, skies are often cloudy, and rain comes frequently.
By late October, rain becomes less predictable, and humidity drops bit by bit.
November stands out as the turning point, when the air feels drier and skies clear up more often.
Early fall demands flexibility due to heavy showers, while late fall brings more stable weather with fewer disruptions from rain.
Humidity, Dew Point, and Comfort Levels
Humidity in Siem Reap stays high during fall, with dew points that create a consistently muggy feel.
Even as rainfall drops sharply through the season, the air still holds a lot of moisture, which affects how warm or sticky the weather feels.
Average Humidity During Fall
Relative humidity in Siem Reap peaks in early fall.
September often hits around 75%, making it the most humid month of the year.
By November, levels drop a bit but still stay above 65%, so the air remains damp even as rain lessens.
You’ll notice that mornings feel especially humid, with levels peaking overnight and just after sunrise.
Afternoons bring some relief as temperatures rise, but humidity rarely drops below the mid-60s.
Compared to the dry season, fall humidity is much heavier.
Even when rain slows down later in the season, the air still feels moist and can make daily activities feel warmer than the temperature suggests.
Dew Point Variations
The dew point tells you how humid the air feels.
In Siem Reap during fall, dew points stay high, typically between 73°F and 79°F.
These values mean the air feels muggy to oppressive—sweat just doesn’t evaporate easily, and things get sticky.
As the season goes on, dew points drop a little.
By late November, they may reach closer to 70°F, which is still humid but more tolerable than early fall.
This shift matches the decrease in rainfall and cloud cover.
If you’re sensitive to humidity, you’ll notice the difference between September’s heavy dew points and the slightly drier air in November.
The change is gradual but real when you spend long hours outdoors.
Perceived Comfort for Visitors
For most visitors, comfort in Siem Reap during fall depends more on humidity and dew point than on temperature.
Even though daily highs average mid-80s°F, the high moisture makes it feel warmer and heavier.
You should expect muggy conditions nearly every day in September and October.
By November, the air gets less oppressive, though it’s still humid compared to many other places.
Light, breathable clothing helps you stay comfortable.
Taking breaks indoors or in the shade during the afternoon can really help.
If you plan outdoor activities, mornings and evenings are usually more pleasant than midday, when both heat and humidity peak.
Cloud Cover and Sunshine Hours
In Siem Reap, fall brings a clear shift in the skies.
The season starts with heavy cloud cover and frequent rain, but conditions gradually improve.
You’ll see more sunshine and fewer overcast days as the months go by.
Trends in Cloudy Skies
At the start of fall, you’ll run into very cloudy conditions.
In early September, skies are overcast or mostly cloudy about 90% of the time.
That’s the tail end of the rainy season, so thick cloud layers are common.
As the weeks pass, cloud cover drops off quickly.
By late November, skies are mostly clear or partly cloudy much more often, with overcast conditions falling to around 55–60% of the time.
Your chances of seeing blue skies improve steadily through the season.
If you visit later in fall, you’ll notice brighter mornings and less afternoon cloud buildup compared to September.
Average Daily Sunshine
Since cloud cover drops through fall, the number of hours with direct sunlight goes up.
In September, heavy clouds often limit sunshine to short bursts, even though daylight lasts over 12 hours.
By November, you can expect longer stretches of bright conditions.
On average, Siem Reap gets between 6 to 8 hours of sunshine per day during the fall months, with more sun later in the season.
The increase in sunshine really matters if you’re planning outdoor activities.
Exploring temples or taking day trips feels a lot more comfortable when skies are clearer and light is more dependable.
Clear Versus Overcast Days
As fall moves forward, you’ll notice a real shift in the balance between clear and overcast days. In September, thick clouds take over most days, and rain usually tags along with those gray skies.
By late November, clear or partly clear skies show up about 40–45% of the time. Sure, it’s not totally cloud-free, but it feels like a big step up from the gloom of early fall.
This shift really changes how you plan your days. Early fall might force you to stay flexible thanks to all the clouds and rain. Later in the season, you can count on better light for sightseeing and photography.
Wind Speed and Other Atmospheric Conditions
Fall in Siem Reap usually brings calm wind conditions, especially compared to other seasons. Speeds generally stay low to moderate, but changes in direction and humidity make the weather feel different each day.
These shifts affect comfort and what you can do outside.
Prevailing Wind Patterns
The move from the wet season into the drier months shapes wind direction in Siem Reap. During fall, winds often switch from the southwest monsoon to lighter breezes out of the northeast.
These changes calm down the storms, though the winds still carry some moisture early in the season. By late fall, winds get steadier and bring in drier air.
You’ll probably notice the winds aren’t strong enough to mess with your plans. Instead, they help take the edge off the humidity that sticks around after the rains. For travelers, that means outdoor spots like temples and markets feel more comfortable.
Wind Speed Fluctuations
On average, wind speeds in Siem Reap in the fall fall between 5 to 10 mph (8 to 16 km/h). Local airport weather stations have tracked these numbers for years.
You’ll feel the calmest air in the mornings and evenings. Around midday, gusts can pick up a bit, but rarely go over 15 mph.
Since the wind stays pretty steady, you don’t have to worry about sudden, strong bursts. The gentle air movement makes planning outdoor activities a lot less stressful.
Impact on Local Weather
Wind speed and direction shape how rainfall and humidity play out in Siem Reap. Early in the fall, winds still bring in moisture, which can mean quick, heavy showers. Later on, the drier winds cut back on rain.
Because the winds stay modest, they don’t cool things down much. Even with a breeze, the days often feel warm thanks to high humidity. At night, though, the air moves just enough to make things less sticky.
If you’re visiting, expect humid but manageable weather. Light winds might not cool you off, but they help clear out leftover moisture and haze after storms, making it easier to see across the city and temple grounds.
Travel Tips for Visiting Siem Reap in Fall
Fall in Siem Reap brings humid afternoons, plenty of showers, and lush green everywhere you look. You’ll need to plan around the weather, pack smart, and pay attention to seasonal travel trends that can impact both comfort and costs.
Best Times for Outdoor Activities
September and October see rain often, mostly as short but heavy afternoon showers. Mornings are usually driest, so that’s the best time for Angkor Wat visits or countryside bike rides.
Sunrise tours draw crowds because skies are clearer and the air feels cooler. By late morning, the heat and humidity climb fast, hitting 30–32°C (86–90°F).
If you want to avoid muddy or slippery paths, stick to paved temple routes or keep hikes short. Boat tours on Tonle Sap Lake work well in fall, since water levels are high and you get better views of floating villages.
Packing Recommendations
You’ll want to be ready for both heat and rain. Bring a lightweight rain jacket, quick-dry clothes, and comfortable sandals or shoes with good grip. An umbrella is handy for sudden downpours, but you can skip heavy coats since it stays warm.
Don’t forget mosquito repellent, especially if you’re out near rice fields or lakes in the evening. A wide-brimmed hat and sunscreen help during sunny breaks.
If you’re heading to temples, pack a small backpack with water, a reusable poncho, and a change of clothes for long days outside. Most hotels offer laundry, so you can travel lighter and wash clothes as needed.
Seasonal Travel Considerations
Fall brings the wet season, so you’ll spot fewer tourists than during the dry months. You’ll probably get lower hotel rates and more flexibility when booking tours.
Some rural roads get muddy, and occasional flooding might slow down your trip. I’d suggest planning extra time between activities, just in case the weather throws you off schedule.
Local tuk-tuk drivers know how to handle wet conditions. Still, if you’re heading outside the city, it’s smart to double-check routes ahead of time.
Festivals like Pchum Ben sometimes happen around this season, so you might catch some traditional ceremonies. Make sure to check dates before you travel, since some attractions could close or run on limited hours during big events.