Reports on impressions and clicks are usually updated every 15 to 30 minutes. Occasionally there will be a delay of 24 hours or more in the reports you have on your site.
When there's a delay, you'll receive this message: "We're sorry, some data in this report is delayed, please try again later. There's no impact to ad serving or payments."
Note: Your reports won't show any data for time periods when no page impressions are generated. As a result, you may have a No data available message in your reports.