The temperature history of four small experimental pavements laid adjacent to the full-scale road experiment at Alconbury By-Pass has been studied in detail. Temperatures in the pavements have been recorded at depths of 20 mm, 40mm, 100 mm, 200 mm and 350mm. There is little major difference in the temperature behaviour of the four constructions. Representative elements of the history of one of the constructions are presented, including temperature variations with depth over 5-6 day periods of uniform hot, warm, cool and cold weather. Two attempts have been made to predict temperature gradients in the pavements, firstly from theoretical heat-flow considerations and, more empirically, from an assumption that the heating/cooling cycle can be representated by a simple harmonic function of time. The validity and accuracy of these predictions are discussed. The climatological significance of the Alconbury site is briefly considered.