As No. 10 typhoons are so rare it is hard to say if they are more frequent at one time of the year or another, but generally over the last 60 years or so they have occurred during the regular typhoon season. In conclusion the Hong Kong Typhoon Season is May through October, with June, July and August being the worse months. Raw data for typhoon graphs from the Hong Kong observatory: http://www.hko.gov.hk/ Typhoons rarely cause serious injury, but that wasn't true in the past.