Temperature related variables

Temperature related variables

 
 
  • Heat-waves are worked out for the summer half-year (April to September). We define a heat-wave as the total length of any period, lasting six days or more, where the maximum temperature each day is more than the 1961 to 1990 average temperatures for those days by at least 3ºC.
  • Air frost happens on a day with a minimum air temperature of less than 0ºC. We only analyse the seasons where air frost is likely to happen (in other words we do not analyse summer temperature information).
  • Ground frost happens when the minimum temperature at grass level reaches 0ºC or below. This is a common event in Scotland, even in the summer.
  • We have assessed the dates of first and last ground frosts from the records from four individual sites. The date of the first frost considers temperatures from 1 August and the last frost examines information before the end of the following July.

Figure 2 – Met Office sites for observing precipitation and temperature (January 2001).