Show events date instead of article date in default calendar widget

I may be wrong but I don’t think you can modify the Calendar Widget at least not that easy as like passing a post type and a field to query for.

You have a few options:

• Create a Widget.
• Create a function like get_calendar() on line 1.406 on general-template.php file (wp 4) and pass it via get_calendar filter.
• Install a plugin that offers an event post type with a calendar widget.

ps: don’t modify general-template.php is a bad practice and when wordpress gets updated you will loose all your modifications.

Read more about it:

• Using a different wordpress function instead of the default one
• Modify Native Calendar Widget for Event Post Types

If you have PHP and MySQL skills this should give you a starting point in how to solve this.

Sorry for bad english.