Annotation - Chapter 1, Page 1
From Riddley Walker Annotations
No dates are explicitly given in the story, but Riddley mentions later that his birthday is "2nd Ful" or the second full moon of the year. Considering the parallels between Riddley's society and ancient Britain, David Cowart speculates that they may date the new year from November as the early Celts did, which would place us near the end of December. BW Riddley mentions later that "Shorsday" (shortest day—the winter solstice, usually around December 21 in the Northern hemisphere) has already come and gone.