Relative operating characteristic (ROC)
yellow, orange and red respectively - and indicate regions with relatively good seasonal prediction skill. Regions with ROC score between 0.6 and 0.7 show skill at lower levels but still better than guessing or use of climatology. Grey or light blue shading is used when scores are below 0.6 (i.e. near or below to the 0.5 'no-skill' threshold, suggesting forecasts in these regions are currently little better than guesswork).