Phnom Penh Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Phnom Penh, Phnom Penh Municipality, Cambodia. Long-term data from 1990 to 2020 was used to calculate these averages. Let's explore the details to provide you with a complete overview.

Phnom Penh experiences significant rainfall throughout the year, averaging 1415 mm (56 in) of precipitation annually. However, this abundant rainfall is not evenly distributed, with a distinct dry and rainy season during certain months. You can clearly see this in our monthly precipitation graphs 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 252 mm (9.9 in) of precipitation, recorded across 19 rainy days.

In contrast, the driest month, February brings less rainfall, with 12 mm (0.5 in) over 2 rainy days.

September, the wettest month, has a maximum daytime temperature of 33°C (91°F). The city receives 129 hours of sunshine in this period. During the driest month February you can expect a temperature of 35°C (95°F). For more detailed insights into the city's temperatures, visit our Phnom Penh Temperature page.

Phnom Penh's average annual precipitation is 1415 mm (56 in). Let's compare this to some popular worldwide tourist destinations:

Chicago, USA, sees an annual precipitation of 1062 mm (42 in), with rain and snow contributing to its humid climate.

In Seoul, South Korea, the average annual precipitation is 1237 mm (49 in), with most rain falling during the summer monsoon season.

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 Phnom Penh's weather, including sunshine hours, humidity levels, and temperature data, visit our Phnom Penh Climate page.