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 Guangzhou is January and the most expensive month to fly is February. (Average prices, based on 234 datapoints.)
The best day to arrive at Bangkok is Sunday and it would be best to avoid Monday, as prices are on average 110.89% higher than on Sunday. (Average prices, based on 385 datapoints.)
The cheapest airline flying from Bangkok to Guangzhou is China Eastern Airlines. They are 52% cheaper than Thai Airways. (Average prices, based on 240 datapoints.)