For alien landing sites, where 3 alien armies would spawn, I suggest including the time for landing and/or the countdown till landing in the UI.
Currently, the only way to find out is to open the Intel menu (which is very slow to load!), go to alien tab, scroll down alien events, find the event dates, recall it's roughly 30 days later the landing happens (though the game says 30 days exact iirc), deduce and compare landing dates to current date. An UI display directly on the landing site prompt would circumvent all that. Would be super nice.