Why Vietnam is three countries in one (and why timing matters more than route).
Vietnam is one of the great travel bargains on Earth, backpackers can live well on $25–35 a day, mid-range travelers on $50–80, the food culture is world-class for a few dollars a meal, and the e-visa system introduced in 2017 (and expanded to 45 then 90 days through 2024–2025) has removed the last real friction. But the country's geography forces a planning decision most travelers don't realize they're making.
The shape of Vietnam matters. Stretched 1,650 km north to south along the South China Sea, Vietnam crosses three distinct climate zones that are often on opposite weather schedules. A two-week trip from Hanoi to Ho Chi Minh City typically passes through all three. Get the timing wrong and you can land in Hanoi in 38°C summer humidity, find Hoi An's Old Town flooded knee-deep, and get Mekong day trips cancelled by storms, all in the same fortnight.
Three macro patterns to internalize:
1) Three regions, three different best times. The north (Hanoi, Halong Bay, Sapa, Ninh Binh) is at its best in March–April and October–November, mild, dry, clear. December through February is cold (Hanoi 13–18°C, Sapa near freezing with occasional snow), grey, and often drizzly with the famous crachin mist. June through August is hot, humid, and rainy, Halong Bay sees its highest typhoon activity in this window. The center (Hue, Hoi An, Da Nang, Nha Trang) is best February through May, sunny, dry, beach water warm. From September through November, central Vietnam is hit by typhoons and seasonal floods: Hoi An's Old Town floods regularly (sometimes meters deep), boat tours cancel, beaches close. The south (Ho Chi Minh City, Mekong, Phu Quoc, Con Dao) runs on a tropical wet–dry cycle: dry November through April, with the wet season May through October bringing predictable, tropical-style 1–2 hour afternoon downpours rather than continuous rain.
2) The two overlap windows. The only times all three regions are simultaneously in good shape are mid-March to late April (the country-wide sweet spot, northern spring, central pre-monsoon, southern dry) and mid-October to mid-November (slightly higher risk because central typhoons can extend into early November, but workable in most years). Most well-built two-week itineraries target one of these.
3) Tet rewrites the calendar. Tet, Lunar New Year, typically falls late January or early February (Tet 2026 = February 17; Tet 2027 = February 6). The official public holiday runs roughly a week (Feb 14–22 in 2026), but the practical impact stretches 3–4 days before through 3–7 days after: domestic flights and trains sold out, sleeper buses fully booked, hotels in major cities full of returning Vietnamese families, family-run restaurants and shops closed, banks closed, ATMs run low on cash, and the immigration department shuts down (so you cannot extend a visa during Tet). Major attractions like Halong Bay cruises run reduced schedules; international hotels and convenience stores stay open. Tet is genuinely magical to experience, flower markets, ancestor altars, fireworks on New Year's Eve, families in traditional áo dài, but you cannot move efficiently during the core week.
The other thing to know: Vietnam is forgiving in shoulder seasons. "Wet season" in the south rarely means all-day rain, it usually means a 1–2 hour afternoon dump, then sun by 5 PM. "Wet season" in the center is a different beast (typhoons, multi-day flood events) and should be avoided more carefully. "Wet season" in the north (June–August) is hot, humid, and storm-prone but rice terraces in Sapa are spectacular green.