Phnom Penh weather by month
Phnom Penh runs from about 27°C in December to 32°C in April, with October the wettest month at 376 mm.
warmest month
April
32°C
coolest month
December
27°C
wettest month
October
376 mm
worst air month
April
45 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 27°C | 3 mm | 321 h | 24 |
| February | 28°C | 5 mm | 314 h | 29 |
| March | 30°C | 12 mm | 343 h | 39 |
| April | 32°C | 12 mm | 353 h | 45 |
| May | 30°C | 257 mm | 290 h | 33 |
| June | 29°C | 171 mm | 270 h | 17 |
| July | 27°C | 283 mm | 238 h | 11 |
| August | 28°C | 239 mm | 319 h | 11 |
| September | 27°C | 352 mm | 233 h | 11 |
| October | 27°C | 376 mm | 267 h | 15 |
| November | 28°C | 121 mm | 313 h | 15 |
| December | 27°C | 78 mm | 274 h | 14 |
About 3,535 hours of sun a year. Roughly 178 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-23. Full method, licences and the list of sources we rejected are on the methodology page.