This study shows the extent of seasonality in home prices in various markets around the United States. Everyone knows there is seasonality in the pattern of sales volumes over the course of a year, but few studies have examined the effect on selling prices. In some residential markets, seasonally induced price effects may significantly add to appraisal error if not corrected. For example, not incorporating seasonal influences on prices can mean missing an average of -2.78% on the downside to 1.93% on the upside in certain Core Based Statistical Areas.