Time of day doesn’t matter, but do think about the first several Pins that you’re saving each day. NOTE: See details below on when the “day” starts.
Because of the new following feed, we may start to see a trend towards specific time of day that people interact with your Pins.
In the following tab, your content is distributed in real time to those following you. Pinterest does not give preference to those who Pin at a certain time of day. Instead, it depends on when your target audience is online and interacting with your Pins that matters.