To increase our possibility to win and profit in investing and trading we got to know seasonal effects on stock markets.This is about understanding existing market patterns and cycles. We explain all these patterns in plain and simple terms that investors or traders can grasp in a short reading period so they could increase an odd on their favor to win or profit in the stock markets.Some investors and traders will be interested in the market patterns and cycles in some points. Some may already have gone on searching this information. Many of them are disappointed as they didn't find it. They will acquire the information here and don't have to read all kind of theories and references that many other books of this kind present. As investors and traders, we just want to know what they are and how good we could and should believe in it.Also, what is the simple logic behind this belief or information? Are they making sense to us? What are their applications? Should we be more comfortable to apply it in our situation? Do they really work? How could we benefit from it and make profit in our investing and trading activities.One of the significant phenomena is the best trading period of the year. It often occurs time after time. Also, we will learn all kinds of seasonal effects which include calendar effects, month of the year effects, government related effects, day and hour of the week and day, and the supply and demand of goods and services.On the month of year effects, we will learn about January barometer, September effect, May principle or Halloween indicator, Mark Twain effect, The Santa Claus rally or December effect, and January effect. On the government related effect, we will be learning about the presidential election effect and the congressional effect. On the demand and supply of goods and services, we will explain on how market supply and demand affect the stock price.