Bhutan has a wide range of temperature and climatic conditions. For instance, while Thimphu is chilly, Punakha can be hot. It is therefore advisable to dress in layers. For protection against cold, layered clothing is better than one or two thick garments. Clothing should preferably be made from natural materials, which allow the body to breathe. Bring comfortable, well worn clothing, and plenty of underwear and socks. If traveling in the cold season, bring two sets of silk vests and long johns, as they are warm and dry quickly after washing.
Dress modestly and respectfully for visits to monasteries, dzongs and other religious institutions. Remove hats, caps etc. before entering, and refrain from smoking on the premises.
The following is a fairly exhaustive list of what you should pack for your trip to Bhutan.
Items that may be of use while traveling in Bhutan: Small day pack; proper pouch to hold your travel documents, money, air tickets and other valuable items/documents; clothes as per season, a poncho or rain gear /or umbrella (June – September); sunglasses/spare glasses, comfortable walking shoes, pocket knife, hat, camera, films and accessories (including spare camera batteries)
These items may not be necessary but if you are keen on it: Insect repellent, hand cream, small sewing kit and safety pins, sun cream, lip salve, soluble aspirin, antiseptic cream, anti-histamine cream, anti-diarrhea pills, a preparation for the relief of sunburn, and any medication you take regularly, or might need to take for a periodically recurring condition, such as asthma. You will be taking more pictures than expected or necessary, so be sure to have good batteries that will last you a whole day or two. There are many dogs in settled areas. They sleep in the day and roam around at night. Bring earplugs if you think their barking might bother you. If you wear contact lenses, bring a pair of spectacles as well, as at high altitudes contact lenses can irritate the eyes.
Trekkers: In addition to the above, bring
Sleeping bag (if you prefer to bring your own) and thermarest, comfortable trekking boots which have already been broken in and plenty of socks, noting that woolen socks dry quicker than cotton ones, facecloth, soap, hair shampoo, cold water detergent; torch or flash light with spare batteries, mirror, scissors. Also bring a water bottle and zip locks plastic bags for packing clothing while on trek.