Temperature related variables

Growing degree days


Figure 12 - Growing degree days for Scottish regions each year, from 1961 to 2003, with smoothed curves showing a running average.

Table 7 - Changes in growing degree days (as a percentage) from 1961 to 2003. Values in bold show that we are 95% confident (statistically) that the change is part of a measurable trend.


North Scotland East Scotland West Scotland Scotland
Growing degree days 23.7% 22.5% 21.1% 22.5%


Regional trends


  • Typical values in the early 1960s were about 950 GDD a year in North Scotland, 1000 GDD a year in East Scotland and 1150 GDD a year in West Scotland.
  • There is a clear trend of an increase in the length of the growing season
  • Increases in the North and East regions are similar, and slightly greater than that of the West
  • This increase is likely to be mainly due to the upward trend in both minimum and average temperatures in the spring. However, increases in autumn temperatures will also add to this.

Spatial trends


  • We can see areas of large increase in the Shetlands and the Outer Hebrides.
  • The central mountainous areas, mainly the Grampians and Trossachs, show the least change.

Future Trends


  • There is no estimate in the UKCIP02 report for this measure.

Figure 13 - Pattern of change in growing degree days (as a percentage) from 1961 to 2003.