Rice Terraces of the North: When Sapa, Mu Cang Chai and Hoang Su Phi Are Green, Flooded and Gold

The northern mountains grow a single rice crop a year, and the terraces change with it: bare and brown in winter, flooded and mirror-like when the paddies are filled and planted from late April to early June, deep green through the summer rains, and gold for two or three weeks from mid-September before the harvest strips them. The photographs people come for are the flooded terraces at planting and the gold at harvest; the green months are lush and cloudy. Plan the dates first and the destination second.

The terraces below Sapa along the Muong Hoa valley to Ta Van and beyond are the accessible ones: an hour's walk from town, seen from every trek, and the reason the trekking guide exists. They are among the steepest in Vietnam and gold in the second half of September. Sapa's cloud and rain are the risk: June to August is the wettest and the valley can be fogged for days.

Mu Cang Chai, in Yen Bai province six to seven hours from Hanoi (and about four from Sapa over the Khau Pha pass), has the terraces the postcards use: the amphitheatres of La Pan Tan, Che Cu Nha and De Xu Phinh, recognised as a national heritage landscape, where the Hmong have carved whole hillsides. The gold season runs from about 15 September to 5 October and the district holds a terrace festival with paragliding off the pass. It is a two-day trip from Hanoi at least, by car or motorbike, and worth it in the harvest fortnight above all.

Hoang Su Phi, in Ha Giang province, is the remote one: terraces on slopes so steep they look vertical, Red Dao and La Chi villages, and almost no other visitors, gold in late September. It is a three- or four-day loop from Hanoi and often combined with the Ha Giang motorbike loop. Pu Luong, south-west of Hanoi in Thanh Hoa, is the gentle alternative: lower terraces, Thai stilt villages and lodges, two crops a year so green more often, four hours from the capital.

For flooded terraces, mid-May; for gold, 15 to 30 September in Mu Cang Chai and the last week of September to the first of October in Sapa and Hoang Su Phi, and book transport and rooms a month ahead, since Vietnamese photographers fill every guesthouse. Weather is the wildcard: the harvest fortnight is also the tail of the typhoon season and fog is normal. Guided treks and private cars from Sapa reach Mu Cang Chai in a day; the best time guide has the Sapa detail.