Siem Reap Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Siem Reap, Siem Reap Province, Cambodia. These averages rely on historical data collected over 30 years, from 1990 to 2020. Let's now guide you through the details for a complete overview.

Siem Reap is known for its substantial rainfall, with annual precipitation reaching 1470 mm (58 in). While the overall climate is wet, there are notable seasonal patterns that create interesting contrasts, as demonstrated in our graph below.

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm (0.01 in))

Significant seasonal changes in precipitation occur throughout the year. During the wettest month, September receives substantial rainfall, averaging 286 mm (11 in) of precipitation, recorded across 18 rainy days.

In contrast, the driest month, January brings less rainfall, with 9.8 mm (0.4 in) over a single rainy day.

September, the wettest month, has a maximum daytime temperature of 33°C (91°F). During the driest month January you can expect a temperature of 33°C (91°F). For more detailed insights into the city's temperatures, visit our Siem Reap Temperature page.

Siem Reap's average annual precipitation is 1470 mm (58 in). Let's compare this to some popular worldwide tourist destinations:

The city of Rome, Italy, has an average annual precipitation of 832 mm (33 in), spread fairly evenly throughout the year.

Beijing, China, receives 560 mm (22 in) of annual precipitation, concentrated in the summer months.

Adelaide, Australia, enjoys 511 mm (20 in) of annual precipitation, with dry summers and wet winters.

Bangkok, Thailand, experiences a tropical monsoon climate with 1668 mm (66 in) of annual rainfall, with the heaviest precipitation occurring during September and October.

Precipitation amounts are measured using specific gauges installed at weather stations, collecting both rain and snow and any other type of precipitation. Rainfall is measured directly in millimeters, while that from snow and ice is obtained by melting it. Automated systems often incorporate heaters to make this easier.

Information from these stations is transmitted via Wi-Fi, satellite, GPS, or telephone connections to central monitoring networks. This information is immediately updated and integrated into weather models and forecasts.

Precipitation has a very strong role in determining the local climate and ecosystem:

• Changing Rainfall Patterns: Global warming causes drastic changes in the patterns of rainfall. Some areas have been experiencing increased frequency and intensity of rainfall, while other areas experience longer dry spells or even droughts.
• Local Impacts: Many regions are experiencing heavier rainfall in the winter months and drier, hotter summers. This affects agriculture, water resources, and ecosystems.

• Mawsynram in India is noted as being the wettest place on earth, with over 11 meters (36 feet) of rain falling every year.
• In contrast, Antofagasta in Chile is among the driest places on the planet, getting less than 0.1mm (0.004 inches) per year, with some years recording virtually no rainfall.
• Nearly 1,650 thunderstorm cells are estimated over the planet at any given time.

For more detailed information about Siem Reap's weather, including sunshine hours, humidity levels, and temperature data, visit our Siem Reap Climate page.