The Wairarapa winegrowing region, a Geographical Indication since October 2017, is one of New Zealand's smallest. It contains two GI sub-regions, Gladstone and Martinborough, as well as Masterton and Opaki. Martinborough was the original area planted, on the basis of careful scientific study in the 1970s, which identified its soils and climate as perfectly suited to the cultivation of Pinot Noir. As a consequence, many of the vineyards established there are older than their counterparts in the rest of the Wairarapa. The area in general lies in the rain shadow of the Tararua Range, which gives it a warm climate with relatively low rainfall. Subtle differences are seen in the wines from the South Wairarapa (which includes Martinborough), which has more maritime influences, to those grown further north in Gladstone and Masterton.