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 August. (Average prices, based on 1231 datapoints.)
The best day to arrive at Taipei is Thursday and it would be best to avoid Sunday, as prices are on average 43.86% higher than on Thursday. (Average prices, based on 1231 datapoints.)
The cheapest airline flying from Taipei to Hong Kong is China Airlines. They are 10% cheaper than EVA Air. (Average prices, based on 1249 datapoints.)
The best time to fly is at around 11. (Average prices, based on 1705 datapoints.)