Flight Don Mueang International Airport departs from Bangkok Don Mueang International Airport at 20:00 and arrives at Chiang Mai Chiang Mai International Airport at 21:15.
The flighttime is about 1h 15m. The distance travelled ("as the bird flies"): 204 Km. So the average speed is roughly 163 Km.
The best day to arrive at Bangkok is Tuesday and it would be best to avoid Saturday, as prices are on average 41.02% higher than on Tuesday. (Average prices, based on 19775863 datapoints.)
We have a lot more statistics for flights SL 520 and between Bangkok and Chiang Mai.