Zillow has some data on how much above average home prices are by month of the year and by US city. In general, prices are higher by about 1-3% in March-June. I assume this has something to do with the U.S. school year. It may be somewhat of a self fulfilling prophecy though. Last time I was in the home buying market, which was almost exactly 10 years ago, I started looking for listings in January, but there really was nothing to look at until March. So people in my city (Philadelphia) don’t start listing until March, and by the time you go through the process it seems like most closings are going to be in the May-June time frame (precisely when mine was). I wonder if refinancings show up as home sales in this data though, or if they have some way of knowing when the properties actually change hands. That could skew the data because people can refinance any time of year, and they are likely to refinance when interest rates are relatively low and prices therefore relatively high.