Last updated: August 21, 2025
September weather in Siem Reap, Cambodia presents a vibrant yet humid atmosphere, with maximum temperatures reaching 35°C (96°F) and an average of 28°C (84°F). Enjoying the warm days requires an adjustment to the high humidity levels averaging around 90%, making it feel even warmer. Rainfall is significant, with 240 mm (9.4 in) expected over approximately 25 days, providing a lush backdrop to this culturally rich destination. Visitors should be prepared for frequent showers, which enhance the beauty of the surrounding landscapes while keeping the temperatures warm and inviting.
In September, Siem Reap experiences a notable transition in its climate, with temperatures beginning to cool slightly as the rainy season progresses. The minimum temperature settles at a comfortable 24°C (76°F), while the average dips to 28°C (84°F), making it one of the cooler months of the year. The maximum temperature hovers around 35°C (96°F), which still allows for plenty of sunny explorations. Compared to the hot months of April and May, September offers a more pleasant atmosphere, with increasingly frequent rains refreshing the lush landscapes. This makes it an ideal time for travelers seeking to experience the stunning temples and vibrant local culture without the oppressive heat typical of the summer months.
September marks a peak in precipitation in Siem Reap, Cambodia, with an impressive 240 mm (9.4 in) of rainfall spread across 25 days. This significant increase continues the upward trend in monsoonal rains that begins mid-year, with August and July also experiencing heavy downpours, averaging 152 mm (6.0 in) and 145 mm (5.7 in) respectively. As the rainy season reaches its zenith, lush greenery envelops the ancient temples and vibrant landscapes, creating a breathtaking backdrop. This surge in rainfall signals not only the heart of the wet season but also lays the groundwork for the lush, fertile environment that defines this region in the months to come.
In September, Siem Reap experiences a peak in humidity, soaring to 90%, which maintains the trend established in the preceding months of August and July. This significant rise in moisture levels marks a stark contrast to the drier conditions earlier in the year, where humidity hovered around 50-55% from January to April. As the region transitions from the harsh heat of the dry season into the lush embrace of the monsoon, travelers can expect a humid atmosphere that contributes to the area's rich biodiversity. Following September, humidity levels begin to taper off slightly in October at 85%, signaling a gradual shift toward a more comfortable environment as the rains continue.
In September, Siem Reap, Cambodia, continues to experience a notably high UV Index of 14, placing it firmly in the extreme exposure category. This trend of elevated UV levels has been consistent throughout the year, with only slight variances, as seen in the preceding summer months where the UV Index also peaked at 14. Travelers should be particularly cautious during this period, as the recommended burn time is just 10 minutes under direct sunlight. As September transitions into October, a slight decrease to a UV Index of 12 is expected, yet the overall theme of extreme sun exposure remains prevalent. Staying informed and protected is essential, so don't forget to check the latest details at Siem Reap UV Index.
UV Risk Categories
September in Siem Reap, Cambodia, brings a delightful blend of sunshine and warmth, boasting 272 hours of radiant daylight. As the year progresses, a noticeable trend emerges: the sun's embrace peaks in the spring months, with March offering a remarkable 326 hours, before gradually tapering off into the heart of the rainy season. While September's sunshine hours are a bit lower than the previous summer months, the glow still provides ample opportunities to explore the breathtaking temples and vibrant culture of the region. As the landscape transitions into lush greenery, visitors can enjoy the natural beauty while savoring the warmth of early autumn days, perfectly complemented by the allure of Cambodia's rich heritage.
In Siem Reap, Cambodia, September is characterized by a notably low likelihood of sunny weather, with only a 9% chance of sunshine. This stark reduction follows a trend from the warm months, where February boasts the highest probability of clear skies at 75%, followed by March at 62%. As the rainy season approaches, the chances dramatically decrease, plunging to just 8% in August and further dropping in September. This pattern suggests that travelers planning a visit during this month should prepare for overcast conditions, contrasting sharply with the brighter months earlier in the year.
In September, Siem Reap, Cambodia, enjoys approximately 12 hours of daylight, maintaining the consistent trend established over the previous months. From March through September, the duration of sunlight levels out, providing travelers and locals alike with ample opportunity to explore the region’s stunning temples and vibrant culture. As daylight gradually reduces in October, it signals a transition to shorter days as the year draws to a close, yet the abundance of sunlight during September ensures that outdoor adventures can be maximized, making it a perfect time for visitors seeking to soak in the natural beauty and rich history of this iconic destination.
As the calendar turns to September in Siem Reap, Cambodia, the gentle breezes that have been a hallmark of the region begin to soften, with average wind speeds dipping to 2.0 m/s (5 mph). This marks a slight decrease from the cooler months of June and July, where the winds picked up to 3.3 m/s and 3.2 m/s respectively. Following the more robust gusts of the rainy season, September typically feels tranquil, creating a serene backdrop to explore the ancient temples. As the month progresses, the winds remain consistent at this languid pace, contributing to a warm, inviting atmosphere that encourages both relaxation and adventure in this captivating corner of the world.
Weather in Siem Reap varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Siem Reap, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present striking contrasts in weather. In September, temperatures range from a minimum of 24°C (76°F) to a maximum of 35°C (96°F), with an average of 28°C (84°F). This month is characterized by high humidity levels at around 90% and significant rainfall, accumulating 240 mm (9.4 in) over 25 days. In contrast, January offers a more temperate climate, where minimum temperatures drop to 15°C (59°F) while averaging 27°C (81°F) and reaching a maximum of 35°C (95°F). Additionally, January sees much lower precipitation, with only 11 mm (0.4 in) over 2 days and a humidity of 55%. For more details on January weather, check out Siem Reap weather in January.
September and February present contrasting weather patterns. In September, temperatures range from a minimum of 24°C (76°F) to a maximum of 35°C (96°F), with an average of 28°C (84°F). This month is characterized by high humidity at 90% and significant rainfall, totaling 240 mm (9.4 in) across 25 days. In contrast, February offers milder temperatures, with a minimum of 17°C (63°F) and a maximum reaching 36°C (97°F), while maintaining a similar average of 28°C (82°F). However, February is notably drier, with only 9 mm (0.3 in) of precipitation over just 2 days and a much lower humidity level of 50%. For more insights on the weather in February, you can visit Siem Reap weather in February.
Comparing the weather in September and March reveals significant differences. September typically experiences warmer temperatures, averaging 28°C (84°F), with highs reaching up to 35°C (96°F). However, this month is also characterized by high humidity levels at 90% and considerable rainfall, averaging 240 mm over 25 days. In contrast, March sees slightly lower minimum temperatures at 22°C (72°F) but higher average highs of 30°C (86°F) and peaks of 37°C (99°F). Notably, March is much drier, with only 40 mm of precipitation over just 6 days and a humidity level of 47%. For more detailed information regarding March weather, you can visit Siem Reap weather in March.
In September, temperatures range from a minimum of 24°C (76°F) to a maximum of 35°C (96°F), with an average of 28°C (84°F). This month sees significant rainfall, with 240 mm (9.4 in) spread over 25 days, coupled with high humidity levels of 90%. In contrast, April boasts warmer temperatures, with a minimum of 20°C (68°F) and a maximum reaching up to 39°C (102°F), while the average temperature stands at 30°C (87°F). Rainfall is considerably lower in April, totaling 86 mm (3.4 in) across just 14 days, and the humidity drops to 55%. For more detailed information, check Siem Reap weather in April.
When comparing the weather in September and May, September tends to be more humid and rainy, with average temperatures ranging from 24°C (76°F) to a maximum of 35°C (96°F). This month receives substantial precipitation of 240 mm (9.4 in) over 25 days, resulting in a humidity level of 90%. In contrast, May experiences slightly warmer temperatures, with an average of 30°C (86°F) and highs reaching up to 39°C (103°F). While it sees less rainfall at 141 mm (5.6 in) over 20 days, the humidity is lower at 78%. For more detailed information on the weather specifics, you can visit Siem Reap weather in May.
When comparing the weather between September and June, we see distinct differences in temperature and precipitation. In June, the average temperature peaks at 30°C (86°F) with a maximum of 38°C (100°F), making it hotter than September, where the average is a cooler 28°C (84°F) and the maximum reaches 35°C (96°F). June also experiences less rainfall, recording 117 mm (4.6 in) over approximately 21 days, while September is much wetter, with 240 mm (9.4 in) across 25 days and higher humidity levels at 90% compared to June's 86%. For more detailed information, you can check Siem Reap weather in June.
When comparing the weather in September and July, we see notable differences in temperature and precipitation. In September, the average temperature hovers around 28°C (84°F), slightly cooler than July's average of 29°C (85°F), although July records higher maximum temperatures, peaking at 38°C (101°F). September also experiences higher precipitation, with 240 mm (9.4 in) over 25 days, compared to July's 145 mm (5.7 in) over 23 days. Additionally, September records a higher humidity level at 90% versus July's 88%, making September feel particularly sultry. For further details on July's climate, check out Siem Reap weather in July.
In comparing the weather between August and September, we observe that both months have high temperatures and humidity levels. August typically experiences slightly warmer temperatures, with minimums of 25°C (77°F) and maximums reaching up to 37°C (99°F), while September sees a slight decrease, with minimums at 24°C (76°F) and maximums capping at 35°C (96°F). Additionally, September is marked by increased precipitation at 240 mm (9.4 in) over 25 days, compared to August's 152 mm (6.0 in) over 23 days. Despite the shift in rain and temperature, both months maintain a high humidity level of 90%. For a more detailed look into August, you can visit Siem Reap weather in August.
In September, temperatures in Siem Reap reach a minimum of 24°C (76°F) and can go up to a maximum of 35°C (96°F), with an average of 28°C (84°F). The month experiences significant rainfall, totaling 240 mm (9.4 in) over 25 days and high humidity levels at 90%. In contrast, October sees slightly cooler temperatures, ranging from a minimum of 22°C (72°F) to a maximum of 34°C (93°F), while maintaining the same average of 28°C (83°F). Rainfall is quite similar, with 238 mm (9.4 in) across 22 days and lower humidity at 85%. Overall, October offers a marginally more pleasant climate compared to September. For more information, check out the detailed Siem Reap weather in October.
In comparison to September, November offers generally milder weather. While September experiences higher temperatures with a minimum of 24°C (76°F) and an average of 28°C (84°F), November's temperatures are slightly lower, starting at a minimum of 21°C (71°F) and averaging around 27°C (82°F). Furthermore, September is marked by significantly more precipitation, totaling 240 mm (9.4 in) over 25 days, whereas November sees a substantial reduction in rainfall to 78 mm (3.1 in) over only 13 days. Humidity levels also drop from 90% in September to 79% in November, making the latter month feel more comfortable. For more details, you can check Siem Reap weather in November.
In September, the weather is significantly warmer and wetter compared to December, with temperatures ranging from a minimum of 24°C (76°F) to a maximum of 35°C (96°F) and an average of 28°C (84°F). This month also sees high humidity levels at 90% and substantial rainfall, totaling 240 mm (9.4 in) over 25 days. In contrast, December boasts milder temperatures, with a minimum of 16°C (61°F), an average of 26°C (80°F), and a maximum of 34°C (94°F). Precipitation drops dramatically to just 23 mm (0.9 in), occurring over only 5 days, and humidity levels decrease to 68%. For more details on the December weather, you can check this link: Siem Reap weather in December.
As September rolls in, Siem Reap's weather showcases its tropical character with high humidity and frequent rain showers, creating a stark contrast to the drier months. Temperatures hover around a warm average, but the consistent precipitation, totaling around 240 mm, ensures that lush greenery flourishes, making it an enchanting time to experience the region's natural beauty. While the daily humidity peaks at a steamy 90%, the vibrant atmosphere and cooler evenings provide a refreshing respite. For more insights into what to expect throughout the year, explore the full details at Siem Reap Climate.