Loei

Loei is Thailand's cool-season escape — temperatures drop near freezing in December and January, and the mountainous landscape feels more like northern Vietnam than tropical Thailand. Phu Kradueng National Park is the province's icon: a flat-topped mesa reached by a challenging 9 km hike, rewarding with cool pine forests, cliff viewpoints, and some of the best camping in the country. Phu Luang Wildlife Sanctuary nearby is less accessible but even more pristine.

Chiang Khan, a riverside town on the Mekong, has become one of Isan's most charming destinations — wooden guesthouses line the waterfront, the morning alms-giving procession mirrors Luang Prabang's, and the Kaeng Khut Khu rapids create a scenic stretch of river. The annual Phi Ta Khon festival in Dan Sai (usually June-July) is one of Thailand's wildest celebrations: locals don colorful ghost masks and parade through town in a fusion of Buddhist and animist traditions. Phu Ruea National Park, at 1,365 meters, offers sunrise views above the clouds.