Figure 3: Expected accuracy of peak timing forecasts for the 2012–2013 season.

Week 47 (2012) through week 48 (2013) forecasts were made for 108 cities, which were then aggregated nationally. Plots present the probability that an ensemble predicted mode peak timing is accurate within ±1 week of the observed ILI+ peak as a function of ensemble predicted peak timing variance log transformed. The blue lines are the 2012–2013 predictions grouped by forecast lead; the red lines are the expected accuracy based on the retrospective forecasts also aggregated nationally (as shown in Fig. 1b).