To correlate the season of the year with the prevalence of slipped
capital femoral epiphysis, we reviewed the cases of 177 patients who had
243 slips during an eleven-year period. We assessed the month when the
patient was seen and the implied time of onset of the slip and found a
statistically significant variation for both. The average time of onset was
mid-June, with a standard deviation of 2.5 months, and was not
significantly different for race, sex, or laterality. We attributed the
increased incidence of slipped capital femoral epiphysis during the summer
to increased physical activity in that season.