They always keep 31, but skip past it: var fdate = (d.getDate() - 1.0) + fhours / 24.0; document.getElementById('date').setAttribute("transform

They always keep 31, but skip past it: var fdate = (d.getDate() - 1.0) + fhours / 24.0; document.getElementById('date').setAttribute("transform", "rotate(" + fdate / 31.0 * -360.0 + ", 400,300)");