Please be aware that Bangkok has multiple airports and that these results are for all airports serving the city.
The best month to fly between Bangkok and Chiang Mai is June and the most expensive month to fly is November. (Average prices, based on 11315 datapoints.)
The best day to arrive at Bangkok is Tuesday and it would be best to avoid Friday, as prices are on average 42.55% higher than on Tuesday. (Average prices, based on 10376 datapoints.)
The cheapest airline flying from Bangkok to Chiang Mai is Thai Lion Air. They are 42% cheaper than Thai Airways. (Average prices, based on 11346 datapoints.)
The best time to fly is at around 5. (Average prices, based on 19693 datapoints.)