Simulated difference in the mean annual number of cooling degree days for the Northwest region, for the 2041-2070 time period with respect to the reference period of 1980-2000 (top). Color with hatching (category 3) indicates that more than 50% of the models show a statistically significant change in the number of cooling degree days, and more than 67% agree on the sign of the change (see text). Mean annual number of cooling degree days for the 1980-2000 reference period (bottom left). Simulated mean annual number of cooling degree days for the 2041-2070 future time period (bottom right). These are multi-model means from 8 NARCCAP regional climate simulations for the high (A2) emissions scenario. Note that top and bottom color scales are different. Increases are simulated everywhere, with the greatest increases occurring in southern Idaho and Oregon and southeastern Washington.