This is the current hour of the year... but rolled back to the beginning of the day.

houroftheyear.js

var timestmp = new Date().setFullYear(new Date().getFullYear(), 0, 1);
var yearFirstDay = Math.floor(timestmp / 86400000);
var today = Math.ceil((new Date().getTime()) / 86400000);
var dayOfYear = today - yearFirstDay;
var currentHourOfYear = dayOfYear * 24 - 24