When to go — North Vietnam

North Vietnam runs on a four-season subtropical climate, very different from the rest of the country, that strongly shapes the travel experience. The cool dry season from October to April is the reference window for the vast majority of visitors.

October to December offers the north's finest conditions: pleasant temperatures in Hanoi (20-28 °C), clear skies, a luminous Ha Long Bay. It is also the rice harvest season in the mountains, with Sapa and Mu Cang Chai's terraces turning gold and amber. January and February mark winter: cool in Hanoi (12-18 °C), sometimes misty and drizzly, and Sapa nights can approach 0 °C. The Tet period (Lunar New Year, usually in January-February) is visually unforgettable — decorations everywhere, fireworks, ceremonies — but transport is saturated and many businesses close for 3-7 days.

March and April are often the most pleasant months for Hanoi: mild temperatures, rising humidity but rainfall still rare, flooded rice paddies in the mountains creating mirror-like landscapes. May to September is the rainy season: suffocating heat in Hanoi (up to 40 °C), maximum humidity, typhoon risk between July and September on the coast. That said, the rice fields reach maximum green in July-August, and the landscapes of Sapa and Ha Giang are at their most spectacular. Visitors who can tolerate the heat find significantly lower prices and less crowded sites.

The overall recommendation: target October-November for the best balance of weather, photographic light and manageable crowds. If you are constrained to the summer holidays, prioritise Sapa (cooler at altitude) and avoid Ha Long Bay in July-August, which is overwhelmed by cruise passengers.