Disable Specific Set of Dates - WordPress Plugin WP Datepicker

WP Datepicker is a lightweight WordPress Plugin with variety of options without worrying about jQuery scripts for every other field in your scripts. It’s a FREE plugin for advanced users obviously, because they can extend it with a little effort. Advanced version is also available with most of the demanded/common parameters under settings page.

You can disable specific set of dates like disable 25th December for specific years.