There is a few things that could cause the anti freeze to overheat and spill out.
One of the main things that will cause this is a plugged or stuck thermostat. That is most the time the problem if your antifreeze is not flowing. A faulty thermostat is what opens and closes depending on water temperature. In the morning for example, when you car is cold, it normally stays somewhat closed until the engine and water temp gets a certain temperature, somewhere between 160 and 180, and then opens up. In your symptoms described it appears that it is worn out and possibly frozen shut, which of course would cause blockage and no circulation through radiator and cause it to back up and overflow.
Another possibility , is the radiator itself is partially plugged, the small little coils that in a sense zig zag back in forth through your radiator, could be clogged, due to over the years, particles from normal radiator breakdown internally, start deteriorating and get trapped or blocked, which of course will cause restrictions and back up.
Conclusion: The thermostat is not a major thing to replace, it normally has just a couple bolts you pull off of the housing, then there is of course a gasket, and then the thermostat, You clean up the old gasket area, pull out small little old thermostat, put in new one, put new small gasket on, put the housing back on, put the two bolts back on, and tighten down, And down deal. Auto Zone can show you on the computer, the diagram, and even if you have car there somehow, point it out, but otherwise can show you where it is on your car, sell you the gasket and new thermostat, and it is pretty easy to do yourself. If having done, your looking around 80 to 100 bucks most non dealer shops. And if you want to have your radiator flushed in case a small blockage, most shops can do this for around 60 bucks. Point is, I honestly believe it is just a bad thermostat. I hope this helped you, have a great day, Mike, fixya expert.