Flight Don Mueang International Airport departs from Bangkok Don Mueang International Airport at 16:20 and arrives at Chiang Mai Chiang Mai International Airport at 17:30.
The flighttime is about 1h 10m. The distance travelled ("as the bird flies"): 204 Km. So the average speed is roughly 175 Km.
The best day to arrive at Bangkok is Monday and it would be best to avoid Saturday, as prices are on average 64.7% higher than on Monday. (Average prices, based on 14873985 datapoints.)
We have a lot more statistics for flights DD 134 and between Bangkok and Chiang Mai.