Please be aware that Beijing has multiple airports and that these results are for all airports serving the city.
The best month to fly between Beijing and Hong Kong is July and the most expensive month to fly is January. (Average prices, based on 245 datapoints.)
The best day to arrive at Beijing is Friday and it would be best to avoid Saturday, as prices are on average 176.33% higher than on Friday. (Average prices, based on 246 datapoints.)
The cheapest airline flying from Beijing to Hong Kong is Hong Kong Airlines. They are 53% cheaper than Cathay Pacific. (Average prices, based on 254 datapoints.)
The best time to fly is at around 20. (Average prices, based on 389 datapoints.)