Lampang has a relatively dry climate compared to the neighboring provinces. In winter (from November to March) the weather is sunny and the temperatures pleasant with cool nights and mornings (14-17 °C or less but it is rare). From March to June, it's summer. April is the hottest month with temperature that can exceed 40 °C at the hottest moment of the day. The rainy season runs from May to the end of October but Lampang receives less rainfall than neighboring provinces and rarely suffers from the flash floods like the one taht affected Chiang Mai in recent years. Even in September, the rainiest month, rainfall barely exceeds 200 mm.
The best time to come to Lampang is from November to April. There is no time of year when it is not advised not to come to Lampang although in August and especially in September it rains more.
See weather forecast in Lampang