Weather will likely play an important role when you plan your trip to Sylhet, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually April and May, with an average temperature of 27°C, while the coldest months are January and December, with an average of 21°C. The rainiest months in Sylhet are June, July, August and May, with each month seeing an average of 872 mm of rainfall.