When to go
The best time of year to visit Phnom Penh is during the dry season between November and February. At this time, the temperature hovers consistently around 30-31°C and rain is rare. Prices peak in the middle of the season, so November or February may just be the perfect times to visit. Phnom Penh isn’t overwhelmingly touristy though, so crowds are unlikely to be an issue, even in the high season.
During the hot season, in March-April, the temperature can soar to an uncomfortably sticky 40°C, and the pollution makes it even more unpleasant.
Then the monsoon season starts, in around May, and peaks in September before tailing off in October. Phnom Penh is pelted with torrential rain which often causes flooding. It’s not out of the question to visit during the rainy season: it usually doesn’t rain all day, everything’s cheaper, and it can be fun to watch Cambodian business continue as usual through knee-deep water.