It is currently not known when Popocatepetl will erupt again. It's most recent eruption was on July 4th 2013. It is generally very hard to know when a volcano will erupt though scientists are finding ways to know when to expect one.
Asked in Volcanoes
What do you call a volcano that will not erupt again?
A volcanic feature that should not erupt again is called extinct. One that is not expected to erupt is called dormant. A volcano that might erupt again is called active. ...