There's nothing like an all-inclusive holiday in Hai Duong to revive you, especially when you know what kind of weather to expect. Here's some information to help you decide when to book: The hottest months are usually June and July, with an average temperature of 29°C, while the coldest months are January and December, with an average of 19°C. February and December are the driest months, while August and September are the rainiest months.