Sara and John say...
Expect a tropical climate when you visit this low-lying country at the northern end of the Bay of Bengal.
The driest and most comfortable time of year to visit is between November and March. Rain can occur, especially early in the period, (when cyclones are still possible) but through much of the winter, days are sunny and clear. Temperatures in the mid-20s Celsius make this a great time for visiting, although the nights can be chilly across some northern areas of the country.
Through the spring months, the temperatures rise rapidly, peaking in the low 40s Celsius inland during April and May. As humidity rises so showers and thunderstorms break out more frequently.
Then from June to September, monsoon rains affect the country on a near-daily basis. Southeastern parts of the country are wettest, and as the swollen rivers flow downstream from the Himalayas, flooding across delta areas is commonplace, sometimes hindering travel. Cyclones can occur at any time during this monsoon period, hitting coastal areas hardest.
Although the cloud-cover means temperatures are a little lower than the late-spring peak, the humidity makes this a less comfortable time to visit than wintertime. But from September onwards the monsoon rains retreat and the skies begin to clear, allowing increasing amounts of sunshine and a fresher feel to the air as the year ends.