The GST model is closely correlated to which other measure?

• A. Precipitation anomaly
• B. Growing degree days (GDD)
• C. Maximum monthly temperature
• D. Relative humidity

Answer: (B)

The GST model centers on the heat that the growing season provides to drive vine development and ripening. Because the key driver of growth in this context is accumulated warmth, a measure that sums heat over the growing season will align most closely with GST. Growing Degree Days captures this exact idea: it adds up daily temperatures above a base threshold to quantify the total heat available for growth. So, when GST indicates more favorable warmth, GDD tends to be higher, and vice versa, making them tightly linked.

The other measures don’t track the same resource as directly. Precipitation anomaly reflects moisture, which affects water stress and disease risk more than heat-driven ripening. Maximum monthly temperature is just one snapshot of heat, not the cumulative exposure that governs development. Relative humidity describes moisture in the air, not the thermal resource the GST model relies on.