You can highlight days, mark them with colored dots, add labels or completely color the background of the days using the marked, colors and labels options. Lets call the dates on which events are mapped as lstdates;

Now, Select The Small Calendar (Say B1:G6), From Home > Conditional Formatting > New Rule;

Lets call the dates on which events are mapped as lstdates; You can highlight days, mark them with colored dots, add labels or completely color the background of the days using the marked, colors and labels options. This article demonstrates how to highlight given date ranges in a yearly calendar, this calendar allows you to change the year and the calendar dates change accordingly.

Set The Rule Type As Use.

Highlighting holidays in the calendar. This offers means to add. Formulas to make the dynamic yearly.