 Even the early research on this topic stressed that the base temperature threshold for accumulation for early versus late budding varieties is likely strongly cultivar specific.Various research worldwide has pointed to base temperatures ranging from 39 to 45 °F (4 to 7 °C), but there has been little confirmation of these thresholds across numerous wine regions and for a wider range of varieties.At the other end of the formula, the calculation for growing degree-days used in viticulture and wine production does not normally use an upper cut-off.