Idaho, state in the northwest region of the united states which, as a wine region, has much in common with its neighbour eastern washington. With vineyards at an elevation of around 2,500 ft/762 m, however, it is close to if not beyond the normal viticultural fringe. Its diurnal temperature variation (see temperature variability) is even greater than that of eastern Washington, with the effect of a paradoxical combination in grapes of high acid and high sugar. This posed interesting challenges for both grape-grower and winemaker in the past. In recent years, however, major developments in the vineyard—lower yields, drip irrigation, open canopies and, above all, planting in warmer localities—have had a dramatic influence on wine quality. In few places has global warming been more of a blessing. Winters can still be severe but rarely as devastating as they were in the 1970s and 1980s. Regarded then as a marginal climate, primarily noted for wines from hardier white varieties such as Riesling, Gewurztraminer, Chenin Blanc, and Chardonnay, Idaho now grows notable wines from Merlot, Cabernet Sauvignon, and Syrah. It is no surprise to find successful Rieslings, from off dry to ice wines.
