When travelling, it's generally smart to pack in preparation for rain or any other conditions that may arise. The rainfall in Ciampino is roughly less than Hong Kong International. You can assume this to be the case over the next 13 days.
We forecast the temperature to be around the 31 °Cs in July, on average. The temperature in Hong Kong International is generally hotter than in Ciampino. Book flights in a timely manner in correlation to your departure date.