Please be aware that Taipei has multiple airports and that these results are for all airports serving the city.
The best month to fly between Taipei and Hong Kong is November and the most expensive month to fly is April. (Average prices, based on 1307 datapoints.)
The best day to arrive at Taipei is Tuesday and it would be best to avoid Sunday, as prices are on average 37.42% higher than on Tuesday. (Average prices, based on 1436 datapoints.)
The cheapest airline flying from Taipei to Hong Kong is Hong Kong Express. They are 40% cheaper than EVA Air. (Average prices, based on 1343 datapoints.)
The best time to fly is at around 22. (Average prices, based on 2590 datapoints.)