It should turn off below 74 degrees. How much below depends on your thermostat.

Thank you so much. We just noticed the lines inside and outside are frozen. Probably why the unit was not shutting off.

I assume you arrived at this conclusion, but if the refrigerant lines are freezing up, you need to turn the system off to avoid damage and call for service.

Check your air filter and cleanliness of the coil.

Service came. Filters are clean and so is coil. He said pressure was a "tiny" bit low. Bottom line, he doesn't know what caused it to freeze. He told us to watch it.

Before the evaporator froze up was there good airflow indoors?

It could be low on refrigerant; could have a restriction somewhere in the refrigerant lines, at the metering device, or the filter drier; or could be quite low on refrigerant.

There is a problem or two that the HVAC technician has to find and fix.