We describe annual and seasonal changes in air temperatures over high latitudes of the Northern Hemisphere during the period 1881–1980. Trends (that is, fluctuations on time scales greater than 20 years) in the average temperature of the Arctic are compared with those of the Northern Hemisphere. Seasonal and regional departures from the long-term trends in the average temperature of the Arctic are identified. Spatial patterns of variation in the Arctic temperature field are determined by principal component analysis and the major characteristics of the time series of the dominant patterns are summarized. Trends in Arctic temperatures have been broadly similar to those for the Northern Hemisphere during the study period. The Arctic variations were, however, greater in magnitude and more rapid. The spatial pattern of change associated with the trend in Arctic temperatures is clearly identified by principal component analysis. It shows that the trends have, in general, been Arctic-wide, but that cer... Abstract We describe annual and seasonal changes in air temperatures over high latitudes of the Northern Hemisphere during the period 1881–1980. Trends (that is, fluctuations on time scales greater than 20 years) in the average temperature of the Arctic are compared with those of the Northern Hemisphere. Seasonal and regional departures from the long-term trends in the average temperature of the Arctic are identified. Spatial patterns of variation in the Arctic temperature field are determined by principal component analysis and the major characteristics of the time series of the dominant patterns are summarized. Trends in Arctic temperatures have been broadly similar to those for the Northern Hemisphere during the study period. The Arctic variations were, however, greater in magnitude and more rapid. The spatial pattern of change associated with the trend in Arctic temperatures is clearly identified by principal component analysis. It shows that the trends have, in general, been Arctic-wide, but that cer...