Many travellers picture Northern Thailand in January as cool all day, almost like spring in Europe. That is the common mistake. Mornings can feel cold, especially in Chiang Rai and the mountains, but sunny afternoons often reach 25–30°C. January also brings dry air, clear mountain views, busy tourist sites, and a growing risk of agricultural smoke later in the month. The best trip matches your route to those changing conditions rather than treating Chiang Mai and Chiang Rai as interchangeable stops. Is January actually cool in Northern Thailand? Expect cold mornings and warm afternoons January is one of the easiest…