SO fiddle

Test Fiddle mainly for SO Questions

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/overcast/jquery-ui.css">
<p>Date: <input type="textbox" id="datepicker" /></p>

CSS

.color.ui-datepicker-other-month .ui-state-default { color: red; }

JavaScript

$(function() {
  $("#datepicker").datepicker({
    beforeShowDay: function(date) {
        return [true, date.getDate() === 1 ? 'color' : ''];
    },
    showOtherMonths: true
  });
});