How well do degree days over the growing season capture the effect of climate on farmland values?

- The use of degree days in Ricardian models is reviewed.
- Daily temperature and degree days are interchangeable over the growing season.
- Seasonal climate effects are significantly different.
- The four season average temperature model is superior to the degree days model.

Farmland values have traditionally been valued using seasonal temperature and precipitation but degree days over the growing season offer a more compact alternative. We find that degree days and daily temperature are interchangeable over the growing season. However, the impact of degree days in spring and summer is quite different. Climate effects outside the growing season are also significant. Cross sectional evidence suggests seasonal temperature and precipitation are very important whereas temperature extremes have relatively small effects.