Seasonality in stock prices and indices refers to the tendency for prices to move up or down in a predictable pattern over time. This pattern can be caused by a variety of factors, like festive seasons or for eg. Monsoon season in India, its spatial and temporal distribution. The strength of the seasonal effect can vary from market to market and from time to time. However, there are some general patterns that have been observed in many markets. For example, the stock market in the United States tends to be stronger in the months leading up to Christmas. This is because investors are more optimistic about the economy and earnings during this time. Similarly in Indian stock markets, the pivotal months continue to be monsoon, which determines the rural demand, hence setting trajectory for future months. Seasonality can be a useful tool for investors, but it is important to remember that it is not a guarantee of future returns. The market can always surprise investors and aberrations in seasonal trends can erupt. But then too it forms a useful trend gauging and bias building tool. It is important to note that these are just general patterns, and there are always exceptions. Use data, to decide your option trading approach. Be a data driven trader