For the 2008 to 2018 period, annual outlooks (hindcasts) of dryness/wetness were made from three years in advance. The outlooks (hindcasts) were then compared to the actual dryness/wetness based on the SPEI values. The probability of the outlook accurately predicting dryness/wetness was then calculated (shown below) for the 11-year period. The outlook accuracy would be 50% each for dryness and wetness if they were equally probable, therefore, only regions which had a better than 50% probability of correct outlook are plotted below.
To see the individual three-year outlook accuracy please click here.