<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
<style>
    .ui-state-default,
    .ui-widget-content .ui-state-default,
    .ui-widget-header .ui-state-default,
    .ui-button,
    .ui-button.ui-state-disabled:hover,
    .ui-button.ui-state-disabled:active {
        border: 1px solid transparent;
        background: none;
    }
    .ui-state-highlight,
    .ui-widget-content .ui-state-highlight,
    .ui-widget-header .ui-state-highlight {
        color: #454545;
        font-weight: bold;
        border: 1px solid #454545;
        background: none;
    }
    .ui-state-active,
    .ui-widget-content .ui-state-active,
    .ui-widget-header .ui-state-active,
    a.ui-button:active,
    .ui-button:active,
    .ui-button.ui-state-active:hover {
        color: #fff;
        border: 1px solid #454545;
        background: #454545;
    }
    td.ui-datepicker-week-end a{
        color: red !important;
    }
</style>
<div id="datepicker"></div>
<script src="https://code.jquery.com/jquery-1.12.4.js"></script>
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
$( function() {

    var holidays = ["20150101","20150112","20150211","20150321","20150429","20150503","20150504","20150505","20150506","20150720","20150921","20150922","20150923","20151012","20151103","20151123","20151223","20160101","20160111","20160211","20160320","20160321","20160429","20160503","20160504","20160505","20160718","20160811","20160919","20160922","20161010","20161103","20161123","20161223","20170101","20170102","20170109","20170211","20170320","20170429","20170503","20170504","20170505","20170717","20170811","20170918","20170923","20171009","20171103","20171123","20171223"];

    $('#datepicker').datepicker({
        dayNamesMin: ['SUN','MON','TUE','WED','THU','FRI','SAT'],
        beforeShowDay: function(date) {
          var editedDate = date.getFullYear() + ('0' + (date.getMonth() + 1)).slice(-2) + ('0' +  date.getDate()).slice(-2);
          if(~holidays.indexOf(editedDate)) {
            return [true, 'ui-datepicker-week-end'];
          }
          return [true, ''];
        }
    });
} );

External CSS

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External JavaScript

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