I have put this down to one thing and that is Google works on Google time about 8 hours behind GMT and all the previous day's calculations are being done sometime during their midnight to 4 am period which equates nicely with 9-12 GMT.
Am I correct or way off?
cornwall
1:25 pm on Mar 6, 2005 (gmt 0)
The changeover is 8am GMT, they stats invariably done by then, so I see no reason to suppose servers are taken up with calculations over the next 4 hours
And I have not found any real problem with AdSense being doing consistently between 9 & 12 GMT