Phnom Penh Climate by Month – Rainy Season, Temperature Averages
Summary
The climate figures for Phnom Penh are averaged from 2016–2025 observations (10 years). Annual rainfall averages about 1,796 mm.
The rainy season runs April–November. The wettest month is October with 315.4 mm across 25 rain days; the driest is January at just 17.6 mm.
The hottest month is April (average high 34.5°C) and the coolest is December (30.4°C).
The most comfortable time to visit Phnom Penh is January — less rain and milder heat.
Local climate notes
Phnom Penh sits at the confluence of the Mekong, Tonlé Sap and Bassac rivers, which keeps humidity consistently higher than inland provinces at the same latitude. Wet-season rain is convective and typically arrives mid-afternoon: clear until noon, then an hour of heavy downpour, worst in Mean Chey and Chbar Ampov where drainage is weakest. From August to October the Tonlé Sap backs up and riverside streets flood locally after heavy rain, even when the rainfall total itself is unremarkable.
— Ban biên tập KhmerMeteo · Meteorological data editors
Monthly averages · 2016–2025
| Monthly averages | High | Low | Rainfall | Rainy season |
|---|---|---|---|---|
| January | 31.4° | 23.0° | 18 mm | 4 |
| February | 32.9° | 23.6° | 18 mm | 3 |
| March | 34.3° | 25.1° | 44 mm | 6 |
| April | 34.5° | 26.0° | 102 mm | 14 |
| May | 33.3° | 26.3° | 196 mm | 25 |
| June | 32.4° | 25.7° | 178 mm | 24 |
| July | 31.7° | 25.3° | 197 mm | 25 |
| August | 32.1° | 25.3° | 219 mm | 26 |
| September | 30.9° | 24.9° | 312 mm | 28 |
| October | 30.5° | 24.4° | 315 mm | 25 |
| November | 30.5° | 24.1° | 157 mm | 16 |
| December | 30.4° | 23.3° | 40 mm | 7 |