The outlier in the scatterplot likely represents an anomaly where the sweater sales significantly deviate from the trend observed with respect to temperature. Given the context of sweater sales being affected by temperature, the most logical interpretation of the outlier would be:
There is a one-day sale on sweaters on a warm summer day.
This option suggests that a unique event (the one-day sale) caused an unusually high number of sweater sales in a typically warm period, significantly deviating from the expected trend based on temperature.