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 May and the most expensive month to fly is November. (Average prices, based on 48480 datapoints.)
The best day to arrive at Bangkok is Wednesday and it would be best to avoid Friday, as prices are on average 35.21% higher than on Wednesday. (Average prices, based on 44956 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 48512 datapoints.)
The best time to fly is at around 22. (Average prices, based on 53330 datapoints.)