high season travelling from US to Hong Kong?

Actually June to September is typhoon season. The high season for travel to Hong Kong is from October through December. This is because the weather is nicest during this time of year.

This is from the Hong Kong International Airport site, so it is definitely reputable.

I've been to Hong Kong last July 2006, it was definitely hot and humid. It was supposed to be rainy, but rains did not come for the week I was there.

Hong Kong's high season, October through late December, is popular for a reason: the weather is pleasant, with sunny days and cool, comfi nights. January, February, and sometimes early March are more cloudy and cold, with occasional showers. Although high humidity might arrive prematurely in March and April, these months are generally pleasant for travelling. By May the temperature is consistently warm and comfortable.

June through September is typhoon season, when the weather is hot, sticky, and very rainy. Typhoons (called hurricanes in the Atlantic) must be treated with respect, and Hong Kong is prepared for these blustery assaults; if a storm is approaching, the airwaves will crackle with information, and your hotel and various public institutions will post the appropriate signals. When a No. 8 typhoon signal is hoisted, activities in Hong Kong and Macau will be effected. For safety, head immediately for your hotel and stay put.