Flight Don Mueang International Airport departs from Bangkok Don Mueang International Airport at 13:45 and arrives at Chiang Mai Chiang Mai International Airport at 15:05.
The flighttime is about 1h 20m. The distance travelled ("as the bird flies"): 204 Km. So the average speed is roughly 153 Km.
The best day to arrive at Bangkok is Tuesday and it would be best to avoid Saturday, as prices are on average 61.63% higher than on Tuesday. (Average prices, based on 19750128 datapoints.)
We have a lot more statistics for flights DD 134 and between Bangkok and Chiang Mai.