Vietnam's busiest periods include December to March, when many visitors seek drier weather in the south and cooler conditions in the north, and July to August, when domestic summer holidays increase family travel. Tết, the Vietnamese Lunar New Year, is a major domestic travel period with changing dates, and transport can sell out while some businesses close. The quieter periods are often May to June and September to October, depending on the region and rainfall. Central Vietnam has a different wet-season calendar from the south, so crowd levels vary by itinerary.

Vietnam's main natural-disaster risks are seasonal flooding, landslides and tropical cyclones. The central coast is most exposed to typhoons and heavy rain generally from September to November, while northern and southern regions have different monsoon patterns. Flooding can disrupt roads, railways and river travel, and mountainous areas may experience landslides during intense rain. Heatwaves can occur before and during the wet season. The drier months are often more reliable for travel, but there is no single low-risk window for the whole country; check regional forecasts and storm warnings.

Vietnam's long shape creates substantial regional climate differences. Northern Vietnam has hot, wet summers and cooler winters; central Vietnam often experiences its heaviest rain from September to November; southern Vietnam has a dry season generally from November to April and a wet season from May to October. December to March is often favourable for southern beach destinations, while spring and autumn can suit northern sightseeing. Summer is hot and humid in many areas, with heavy showers. Choosing dates by region is essential when combining Hanoi, central coast destinations and Ho Chi Minh City.

Hotel prices in Vietnam rise during Tết, the Lunar New Year period, when domestic travel surges and some businesses close, and during Christmas and New Year in popular tourist areas. December to March can also be busy in southern beach destinations and major sightseeing centres. July and August bring family-holiday demand at some coastal resorts. Better value may be available in shoulder periods such as May to June or September to October, though rain and storms affect different regions at different times. Check local Tết dates and cancellation conditions before booking.

Flights from Australia to Vietnam often cost more around December and January, Australian school holidays and Tết, when demand from holidaymakers and people visiting family increases. Fares to beach destinations may also rise during local peak seasons, while domestic flights can sell out around Lunar New Year. May to June and September to October may offer better value outside holiday peaks, but weather varies by region. Compare Hanoi, Ho Chi Minh City and Da Nang when they suit the itinerary, and book early for Tết and Christmas travel.