A study in Growing Degree Days
50 years of Growing Degree Days across Australian wine regions
Growing Degree Days (GDD) are a useful measure of accumulated heat, but climate change is altering the conditions around that heat. This study examines 50 years of Australian wine-region climate data to understand how GDD has changed, where traditional GDD remains useful, and where a broader climate-pressure interpretation can improve how we understand regional growing conditions.
The study introduces Hambrook Pressure-Adjusted Growing Degree Days (HP-GDD). HP-GDD keeps Raw GDD visible, then adds transparent adjustments for frost, harvest rainfall, heat, diurnal range and radiation.
Explore the study- Wine regions
- 64 official regions
- Seasons analysed
- 50
- Climate datapoints processed
- ~108 million
- Climate-pressure components
- 5
- Study period
- 1976-77 to 2025-26
- Varieties analysed
- 101