Wiktionary
at all hours
prep.phr. (context temporal location idiomatic English) Late into the night or early morning; when people ought to be sleeping.
Usage examples of "at all hours".
Patrick's, and at all hours of the day the objects could hear their magpie cries.
His coach was seen at all hours in the town and on the Pawtuxet Road, and he dropped little by little the air of forced geniality with which he had latterly sought to combat the town's prejudice.