Keep in mind that this is an 'average' and that exogenous events can greatly affect the normalized results.
Chart courtesy of friend Brian at ContraryInvestor. 
Gold Seasonality with Gold 2010 Daily Price Chart Overlay
"You are the very cause of your ignorance, yourselves. You put away the light, yourselves; you first pluck out both your own eyes, yourselves; and after that other men’s too, so that the blind may lead the blind, until you both fall into the pit.”
Thomas More, The Sadness of Christ (Gethsemane), Tower of London, 1535