The ideal season to visit Hanoi and the north (Mai Chau, Ninh Binh, and Ha Long Bay) is from October to early May. Temperatures can fall to -0°C in the far north (Ha Giang, Sapa) in December and January. From late May to September is the northern hemisphere’s wet season, when large rainstorms are likely to occur sporadically.
The most comfortable months to go to central Vietnam are January through May, with the best time to visit Hue, Hoi An, Danang, Quang Binh, Quy Nhon, Phu Yen, and Nha Trang being from late November to August. Between June and August, when temperatures are typically 35°C, it can get very hot. There may occasionally be floods in central Vietnam throughout the months of September through early November.

From late October to early April is the ideal season to explore south Vietnam (Ho Chi Minh City, Mekong Delta, Phu Quoc, Con Dao, Mui Ne). You may anticipate hot, muggy weather with afternoon downpours that continue for at least an hour throughout the southern region’s wet season, which runs from late May to September.