The best time to trek in Bhutan is the autumn season, between late September and November, when there are clear skies and it is generally dry. Spring, from March to May is another good time to trek in the country. There might be odd rain or snow showers, but the rhododendrons and wild flower are in full bloom during this time and offer a colorful landscape to trekkers.
All foreign nationals except Indian, Maldivian and Bangladeshi nationals will require a visa to enter Bhutan.
You can enter Bhutan from entry points shared with India- Phuentsholing, Gelephu and Samdrup Jongkhar. There are Drukair and Bhutan Airlines flights to Paro,the only international airport in Bhutan. Flights are available from the following cities- Bangkok, Delhi, Kolkata, Bagdogra, Bodh Gaya, Dhaka, Kathmandu, Guwahati, Singapore and Mumbai.
The local currency unit is ngultrum (Nu). There are 100 chetrum in one ngultrum, and 60 ngultrum converts to approximately US $1.00. US Dollars are accepted at most tourist areas and there are foreign exchange services available. There are very few ATMs in Bhutan, so most people prefer to carry cash. The Indian Rupee can be used in Bhutan, the Bhutan Monetary Authority doesn’t allow 500 and 1000 Rupee notes to be traded in Bhutan. The Thai Baht cannot be exchanged in Bhutan.