Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 15:05 and arrives at Chiang Mai Chiang Mai International Airport at 16:25.
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 Wednesday and it would be best to avoid Friday, as prices are on average 43.72% higher than on Wednesday. (Average prices, based on 12723927 datapoints.)
We have a lot more statistics for flights TG 112 and between Bangkok and Chiang Mai.