Above is the daily performance changes for the European DAX index throughout the entire year.

This table shows collectively the last 5 years of each day of the year. As you see there are weak days and there are strong days. It is not to say that these patterns are the same every year, it just gives you a clear overview of the past.

Years 2016 + 2017 + 2018 + 2019 + 2020 = the table.