Please be aware that Kuala Lumpur has multiple airports and that these results are for all airports serving the city.
The best month to fly between Kuala Lumpur and Kota Kinabalu is January and the most expensive month to fly is June. (Average prices, based on 2012 datapoints.)
The best day to arrive at Kuala Lumpur is Wednesday and it would be best to avoid Friday, as prices are on average 76.36% higher than on Wednesday. (Average prices, based on 4116 datapoints.)
The cheapest airline flying from Kuala Lumpur to Kota Kinabalu is AirAsia. They are 36% cheaper than FireFly. (Average prices, based on 2053 datapoints.)
The best time to fly is at around 10. (Average prices, based on 4254 datapoints.)