If your Windows taskbar clock doesn't show current date, you may find it useful to show current date on Screen Calendar tray icon. This option is available in Main settings tab ('Show current date on icon').
As you probably know, tray icons can be shown or hidden. If you want to always see Screen Calendar icon with current date near your clock, you must set to show icon and notification. To do that, right-click taskbar, then click 'Customize notification icons':