Gold Seasonality

According to the Equity Clock website, gold futures contract has seasonal strength from September - May.

With a buy date of September 13 and a sell date of May 23, investors have benefited from a total return of 183.61% over the last 10 years. This scenario has shown positive results in 9 of those periods.
Conversely, the best return over the maximum number of positive periods reveals a buy date of September 16 and a sell date of May 20, producing a total return over the same 10-year range of 159.82% with positive results in 10 of those periods.

http://charts.equityclock.com/gold-futures-gc-seasonal-chart

I've requested seasonal charts for the TSE Global Gold Index and will post if they supply it.

When I look at the chart they provided it looks to me like there's weakness from mid-February through till mid-April. Will update this if I can get further info from them.