The monsoon arrives already in the first days of May, and bursts into heavy rainfall, particularly in the highlands. However, the months is still quite good for a travel to Cambodia. There is still enough of sunshine, especially along the coastal line, for the beaches are the least affected by rains. Tourists come in fewer numbers for fear of the monsoon, so you may also benefit from less crowdedness. Overall, when mountain hiking becomes problematic, the beach holiday is still delightful, even more than in March or April, as the air temperature drops down slightly, making your life more comfortable.
In June things get worse, air temperatures lower a bit, but the main problem is rainfall. Southern beaches, mountain areas, and northern countryside see lots of rain this time, and though some sunshine is visible between the showers, it doesn’t help to drain the wet, and many areas are difficult to access.
Late July brings a lot of misery to the country, as it’s the peak of rains, when it pours every two out of three days. Many areas, including the very capital of Cambodia Phnom Penh, are merely flooded. Roads are dirty and barely crossable, therefore outdoor activities like biking, hiking, and even boating are out of question at this time of the year. Monsoon misfortune continues well into early August. Closer to the end of month the rains gradually become less frequent, but still remain a large problem.
Rainy days still prevail over the dry periods starting in September-October, many areas are still flooded, and some tourists come to see a rare spectacle of floating villages, explore drowned forests, see swelling water basins, and flowing waterfalls. Though it won’t rain all day long, or a couple of days in a row, the showers are likely to continue for hours. Therefore, the months are not recommended to travel to Cambodia. The only merit of the season must be lush vegetation that starts thriving in these pouring rains.