No i never see any patterns that are often mentioned, if electricity went out across half the UK, USA or India then i would expect a sharp drop. But usually i dont see differences on specific days or times of a month.
When you mentioned "black out" ... *sort of off topic* Did anyone have a tremendous drop in earnings when most of the north eastern seaboard (Canada + US) had that 3 day blackout a few summers ago?
Nope, click values seem to be holding steady for me while traffic & number of clicks is up. CPC is almost exactly the same as last month. Maybe your niche/topic lost an advertiser due to economic conditions? I imagine so, but I'm too newbie to have any personal experience with that
Northeast Blackout of 2003 I remember how hot it was with no air conditioning I wasn't with adsense in 2003... so I have no reports of earnings drop then, but I imagine there was!
Too early to tell. I got 4 clicks on May 1st, 5 clicks today (May 2nd) and I didn't get any clicks 3 days in a row before may. so good start this month.