You can find seasonality in all markets but I personally think there is a big difference in "reliability" or "strength" of seasonality in the markets. I personally think seasonality is strongest in the commodity markets. In all markets where you have a physical product and a production cycle during the year. Because the production cycle is always the same you get typical seasonal behaviors in these markets. Other markets, like the indices, also show a seasonal pattern but I think it is not as strong as in the commodity markets. Anyway, seasonality is only one criterion besides others and I would never recommend any entry just based on statistics. You have to look at the current chart of the current spread to see what is going on. That's what we have to trade!