Many Assets, especially Commodities , have patterns of seasonality: Periods in the year when they have shown a greater tendency to rise or a greater tendency to fall.
The Seasonality of an asset is based on historical data (20yrs+): Specific asset seasonality charts can be found via an online search.
This is a simple tool that allows users to highlight and color code each of the 12 months of the year; depending on the seasonality of the specific asset.
The above chart shows Sugar Futures ; which are a seasonal 'sell' in February , and a seasonal 'buy' in May and August.
Seasonality should only be used to compliment a trading setup, NOT as a single reason in itself to buy or sell. Simply put: if you find a good setup, AND you have seasonality on your side; your odds of success are increased.