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 Singapore is August and the most expensive month to fly is May. (Average prices, based on 1548 datapoints.)
The best day to arrive at Bangkok is Wednesday and it would be best to avoid Monday, as prices are on average 57.9% higher than on Wednesday. (Average prices, based on 3059 datapoints.)
The cheapest airline flying from Bangkok to Singapore is Thai Lion Air. They are 64% cheaper than Singapore Airlines. (Average prices, based on 1570 datapoints.)
The best time to fly is at around 17. (Average prices, based on 4296 datapoints.)