Please be aware that Jakarta has multiple airports and that these results are for all airports serving the city.
The best month to fly between Jakarta and Penang is February and the most expensive month to fly is June. (Average prices, based on 5040 datapoints.)
The best day to arrive at Jakarta is Friday and it would be best to avoid Thursday, as prices are on average 19.87% higher than on Friday. (Average prices, based on 7192 datapoints.)