There are three main seasons for climate in Myanmar :

1.The hot season from March to May,

2.The wet season from June to September

3. The cool season from October to February.

Although it is a year-round destination, the best time to visit Myanmar is the cool season when the temperatures are more moderate and there is little or no rain. If you plan to visit Myanmar in cool season, you should make reservation in advance to avoid any fullybooked

Hope this help