10th July 2015: until the end of the current Year of the Red Solar Moon is just half Lunar month left
More pictures can be seen here:
In my opinion, on the outer ring are depicted the 13 days of the current Wavespell of the Yellow Human according to the Mayan calendar Tzolkin.
This crop circle has appeared on 10th July 2015.
The 13th Lunar month, like every other Lunar month, has 4 weeks of 7 days each.
The 13th Lunar month began on 27th June 2015 and continues until24th July 2015.