Question

With default view set to agendaWeek. If I load fullCalendar at 11:59PM the today day slot is not automatically updated after 12:00AM until I refresh the browser.

Answer 1

This is how I fixed it:

Call a function every 5 minutes (or any interval that suits your requirements)

$(function() {
    var tInterval = 5*60*1000;
    timelineInterval = window.setInterval(updateFcToday, tInterval); // Update timeline after every 5 minutes
});

Add a function like this to the page that contains your calendar:

function updateFcToday() {
    var curTime = new Date();
    if(curTime.getHours() == 0 && curTime.getMinutes() <= 5) // this five minutes is same interval that we are calling this function for. Both should be the same
    {// the day has changed
            var todayElem = $(".fc-today");
            todayElem.removeClass("fc-today");
            todayElem.removeClass("fc-state-highlight");

            todayElem.next().addClass("fc-today");
            todayElem.next().addClass("fc-state-highlight");
    }
}