Looking at historical Monero hash rate data it appears as if the hashrate is often the highest near 0:00 GMT and lowest near 12:00 GMT
What credible explanations are there for this pattern? What reason would (a small percentage of) miners have to turn on/off depending on the time of day and continue that pattern over a long period of time?
The daily variance appears to be limited to about 10% of the hashrate. Two possible explanations:
A system administrator mines Monero at night when computers would otherwise be idle
A system administrator mines Monero during the day while having physical control of the computers.
Replace system administrator for anyone with control over a large group of computers and adjust day/night to match the idle computer or working hours in that particular time zone.
In addition to the (very likely) reasons given by Big Things, there is also the distinct possibility that something in the difficulty adjustment algorithm is causing this. It could be the way we're cutting off outliers, for instance. One of the MRL projects is to investigate the difficulty adjustment algorithm precisely for this reason:)
This could also be market driven.
The price of Monero has been swinging whole % points daily.
It's possible someone is mining to pick up some extra XMR to dump for profits.
