time appointed. Septuagint and Syriac say the plague lasted only till noon. So this "time" may mean for the evening sacrifice, 3pm (Compare 2 Samuel 24:18).
Related Commentaries of 2 Samuel 24:15
2 Samuel 24:15
15 So the LORD sent a pestilence upon Israel from the morning even to the time appointed: and there died of the people from Dan even to Beersheba seventy thousand men.