Weather is probably a major factor when you plan your trip to Ninh Hai, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually June and May with an average temp of 83°F, while the coldest months are January and February with an average of 76°F. The rainiest months in Ninh Hai are November, October, September, and May, with each month seeing an average of 10 inches of rainfall.