Using annual temperature values for only nine northern hemisphere stations, in the latitude belt from 43¿ to 67 ¿N, an estimate can be quickly obtained for the departure of hemispheric temperature from its average. A multiple correlation coefficient between this independent variable and the station values of 0.81 accounts for nearly two thirds of the variance. In the 77-year interval 1899--1975 the regression equation gave values with the correct sign of departure in 68 years, of 88 per cent of the cases.