Pest Organisms / German Cockroach
Seasonality
for German Cockroach
This roach is strictly an indoor dweller: it does not come in from outdoors on its own but is moved around entirely by people and lives only indoors. Source: https://schoolipm.tamu.edu/forms/pest-management-plans/ipm-action-plan-for-german-cockroaches/
Since indoor conditions, not the outdoor calendar, drive its activity (an inference, not stated in the source), and since indoors it breeds continuously with many overlapping generations at any moment, infestations run essentially year-round. Source: https://ask.ifas.ufl.edu/publication/IN128