Temperature related variables

Ground frost


Figure 24 - Days of ground frost for Scottish regions each year from 1961/61 to 2004/05, with smoothed curves showing a running average.

Table 13 - Changes in days of ground frost between 1961/62 and 2004/05. 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
Spring -11.4 -8.7 -7.5 -9.4
Summer -3.0 -1.8 -1.4 -2.2
Autumn -7.8 -4.1 -4.3 -5.6
Winter -8.2 -8.4 -9.8 -8.7
Annual -31.8 -25.2 -25.2 -27.8


Regional trends


  • Ground frost, which happens when the minimum grass temperature falls to 0°C or below, is a common event in Scotland, even in the summer.
  • Since 1961 there has been a reduction in the number of days of ground frost in every season, and for each of the three Scottish regions.
  • We can see a downward trend in spring, summer and winter in all regions, as well as for autumn in North Scotland.
  • There is also a measurable downward trend in the number of ground frost days over the year.
  • The steady reduction in the number of days of ground frost each year appears to have begun in the 1980s.

Spatial trends


  • There has been a reduction in the number of days of ground frost for most areas in all seasons. We can see this especially over the western Highlands and Hebrides in spring.
  • The number of days of ground frost has actually increased in winter on both the Shetland and Orkney Islands.

Future trends


  • The UKCIP02 scenarios report does not provide an estimate for future ground frost. However, the expected increase in minimum temperature means that the number of frosts should reduce.

Figure 25 - Patterns of change in ground frost (in days) between 1961 and 2005 for each season.