When to go to Sapa

The best time to visit Sapa as well as the northern mountain is from September to November or from March to May, when the weather is fairly settled with dry sunny days and clear cold nights. In April and May, Sapa is blooming with flowers and green pastures.

Winters can be decidedly chilly, especially in the Northeast where night frosts are not uncommon from December to February, but the compensation is daybreak mists and breathtaking sunrise views high above valleys filled with early-morning lakes  of cloud.
The rainy season lasts from May to September, peaking in July and August, when heavy downpours wash out bridges, turn unsealed roads into quagmires and throw in the occasional landslides for good measure.