Which statement about the GST (Growing Season Temperature) model is true?

• A. It uses the mean temperature of the whole growing season and groups into climatic bands ranging from cool to hot
• B. It relies on rainfall patterns to define climate bands
• C. It ignores the growing season and focuses on the calendar year
• D. It is not correlated with growing degree days

Answer: (A)

GST is defined by the mean temperature over the grape-growing season, and it classifies climates into bands from cool to hot based on that average. This temperature-based approach captures how warm the season is and how it affects grape ripening, regardless of rainfall patterns or the calendar year. Since growing degree days measure heat accumulation over time, higher mean growing-season temperatures generally correspond to more heat units, linking GST to heat accumulation. That's why the statement describing GST as using the growing-season mean temperature and grouping climates into cool-to-hot bands is the best fit.