Typical for the tropical climate of Vietnam, Hoi An and Da Nang city possesses warm weather the whole year with its average temperature of 29 Degree Celsius. The city only has two main seasons: rainy and dry seasons instead of four seasons like in Northern Vietnam.
Although the temperatures are warm throughout the year, the hottest months on average are June and July, during which time the daily high temperatures will be in the mid 35C-37C. The nighttime temperatures during these months will drop to the 30C-32C. The coldest months of the year are December and January. During these months the daily temperatures will be in the upper 22C-25C, and will drop to the mid 18C during the nights.
Generally more important to visitors than temperatures is the rain. The rainy (or monsoon) season in Hoi An and Da Nang is from October until January. During this time, rain clouds will constantly move through the area, particularly during November. It can rain constantly and there is a high probability of flood and typhoons. There are days during which sunshine is abundant, but they are not the majority. This is still considered high season in Hoi An.
The dry season is from February until July. These months provide plenty of sunshine, with warm temperatures.
The best time to visit Hoi An and Da Nang is between February and April, when rainfall is low and temperatures are comfortable. From May and June, it is the summer, the temperatures can get hot.
In Hoi An, They celebrate the Full Moon Festivals in every month and the city becomes the stage for traditional songs, dancing, games and special vegetarian versions of all the local speciality dishes, with lanterns lining all of the streets.
You should experience Hoi An and Da Nang once at least!