Summer learning loss (SLL) is a familiar and much-studied phenomenon, yet new concerns that measurement artifacts may have distorted canonical SLL findings create a need to revisit basic research on SLL. Though race/ethnicity and socioeconomic status only account for about 4% of the variance in SLL, nearly all prior work focuses on these factors. We zoom out to the full spread of differential SLL and its contribution to students' positions in the eighth-grade achievement distribution. Using a large, longitudinal NWEA data set, we document dramatic variability in SLL. While some students actually maintain their school-year learning rate, others lose nearly all their school-year progress. Moreover, decrements are not randomly distributed--52% of students lose ground in all 5 consecutive years (English language arts).