Most of Myanmar has a tropical monsoon climate with three seasons:
Cool – November to February is warm to hot during the day and the air is relatively dry.
Hot – March to May is intensely hot in most of the country. In the cool and hot seasons, you are unlikely to experience any rain. Rainy – June to October is the monsoon season, with high rainfall. From June to August, rainfall can be constant for long periods of time, particularly on the Bay of Bengal coast and in Yangon and the Irrawaddy Delta. In September and October, the rain is less intense and you will experience more sunshine.
TIMES TO VISIT AND REGIONAL VARIATIONS
The most comfortable time to visit is during the cool season, which is also the least humid time of year and has the clearest air – however, this is also the peak tourist season. If you can put up with the heat and/or rain, then you will find it easier (and often cheaper) to book accommodation outside the cool season, and there will be less crowds at popular destinations.
From February until the beginning of the rainy season, much of the country (particularly north of Yangon) can be dusty and hazy, sometimes hindering long-distance views.
Myanmar is a large country and temperatures can vary significantly. As a general rule, temperatures and humidity become lower at higher altitudes; in Chin State in the west and parts of Shan State in the east, temperatures can get close to freezing, and in the Himalayan far north they may drop below zero.
Monsoon rains are the most persistent in Yangon and the south and west; in the centre of the country, around Mandalay and Bagan, showers will generally be more sporadic in the rainy season (and you are likely to experience more sunshine).
With generally high temperatures in the popular locations around the country, lightweight cotton and linen clothing is recommended for most of the year; warmer clothes may be needed for the evenings, which can sometimes be cool. Even outside the rainy season there can on occasion be downpours, so it is advisable to pack a light raincoat. Travelling to higher altitudes and further north, it is advisable to take warmer clothes, particularly in the cool season, when temperatures can drop significantly.