Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 20:20 and arrives at Chiang Mai Chiang Mai International Airport at 21:40.
The flighttime is about 1h 20m. The distance travelled ("as the bird flies"): 221 Km. So the average speed is roughly 166 Km.
The best day to arrive at Bangkok is Tuesday and it would be best to avoid Thursday, as prices are on average 183.36% higher than on Tuesday. (Average prices, based on 8399959 datapoints.)
We have a lot more statistics for flights PG 239 and between Bangkok and Chiang Mai.