Weather in Siem Reap in September 2025
Average weather
Average temperature in Siem Reap in September
Going from a maximum of +91°F during the day to a minimum of +77°F during the night, the temperature in September averages around +88°F.
The average maximum temperature goes up 13% by the end of the month, compared with the beginning of the month, from +88°F to +90°F.
Is Siem Reap warm or cold in September?
Siem Reap is typically hot in September.
Maximum temperatures go down compared to the previous month from +90°F to +88°F. The minimum temperature also goes down from +79°F to +77°F.
Make sure that you pack your summer linen and swimming costumes; it’s probably going to be hot.
September is one of the coolest months in Siem Reap, here is the comparison with other months:
Climate in Siem Reap in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +90°F | +88°F | +88°F | ||||
| Min. temperature | ||||||
| +75°F | +72°F | +66°F | ||||
| Max. temperature | ||||||
| +97°F | +97°F | +93°F | ||||
| Rainfall | ||||||
| 155 mm | 253 mm | 232 mm | ||||
| Wind | ||||||
| 2 m/s | 1 m/s | 1 m/s | ||||
| Humidity | ||||||
| 79% | 83% | 83% | ||||
| Air pressure | ||||||
| 1006 HPa | 1007 HPa | 1009 HPa | ||||
| Sunny days | ||||||
| 0 | 0 | 0 | ||||
| Cloudy days | ||||||
| 2 | 1 | 4 | ||||
| Rainy days | ||||||
| 28 | 28 | 26 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September weather is still as ok as in August. It’s getting colder in September. From +90°F in the day, the average maximum temperature lowers to +88°F. Prepare for more rain. Average rainfall goes from 155 mm to 253 mm. Humidity rises from 79% to 83%. Winds are calmer in comparison to August, going down from 2 m/s to 1 m/s on average. The amount of sunny days stay about the same, averaging 0 sunny days during the month.
October brings much the same weather, it remains ok.
Wind
The average wind speed is 2 m/s getting up to 3 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Siem Reap is gradually decreasing during September, going from 2 m/s to 1 m/s over the course of the month.
Rain
How was the weather last September in Siem Reap?
Climate Change Over the Years
The climate in Siem Reap in September has not changed that much over the last 43 years.
The average temperature was the lowest in 1999 (+88°F) and the highest in 2015 (+92°F). The driest year was 2015 with only 880 mm of rainfall, and the wettest year was 1999 with 1854 mm.
FAQ
Is September a good time to visit Siem Reap?
Can you sunbathe in Siem Reap in September?
Is Siem Reap rainy in September?
Is it sunny in Siem Reap in September?
Other cities in Cambodia
Monthly weather in Siem Reap
Source of the data
For this page, we’ve looked at the typical weather in Siem Reap, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.