Temperate

temperate, a broad class of climates, usually taken to include those with an annual average temperature of less than 20 °C/68 °F, but a warmest month average temperature greater than 10 °C/50 °F, the latter being the approximate poleward limit of tree growth.

Just as wine is considered a beverage of temperate people, so the grapevine is a plant of temperate climates. It is specially so when the grapes are to be used for winemaking, and still more so for table wines. Excessive heat during ripening leads to a loss of the more delicate fruit aromas and flavours from the grapes, and therefore from the wines. Insufficient warmth leads to incomplete ripening in which flavour compounds, which become manifest only late in the ripening process, are lacking. (The gross geographical limits for commercial viticulture resulting from temperature constraints are noted under latitude.)