Bangladesh holds the Sundarbans' tidal mangrove forest with Royal Bengal tigers, the longest natural beach at Cox's Bazar (120km), and the river delta culture along the Padma and Jamuna confluences.
Cool dry season with Sundarbans tiger tracking at peak, Dhaka's air pollution still rough but evenings pleasant, and Cox's Bazar comfortable.
Pre-monsoon with rising humidity and dust, but Sylhet tea gardens at their freshest before summer rains begin in earnest.
Monsoon flooding affects much of the country, river travel becomes the main transport mode, and Sundarbans excursions suspend.
Durga Puja festival fills Dhaka with elaborate pandals, and post-monsoon greenery is lush before dry-season dust returns.