This bar chart shows the n-day return on investment (ROI) averaged over each month. If you would have bought an asset in a particular month and sold n days later (n = 30, 60, 90, 180, 1Y, 2Y, 3Y or 4Y), the bars show your average ROI for that purchase month. The y-axis values should not be interpreted too literally as they are heavily influenced by outlier data from the earlier days for many coins. This can be filtered out by starting the calculation at a later year than the asset's year of inception. Historically for Bitcoin, Ethereum and many altcoins the summer months tend to yield the lowest 180-day ROIs. Q4 through Q1 have historically represented better times to buy.