But my system, like most, does not set production records around the summer solstice. Instead, it is pointed for best year-round production. My system sets records in March, April and May. The all-time record was set April 24 of this year: 89.1 kWh.
But some people like QueenBee have flat roofs and their systems DO peak around this time. His system with 73 panels put out 93.2 kWh on June 21. His record was set May 30, 2014 at 94.7 kWh.
Peak production is always during the spring (March, April and May), with a typical production of around 1,040 kWh during those months. By the time June rolls around, the combination of heat and increased clouds from the rainy season cuts production down into the mid 800s. Overall, at this latitude (26 degrees, N), the yearly production curve is pretty flat. The December minimum is still in the mid 700s.
I have a small system, 10-panel, 2.5 kW in SoCal.
On June 21, my system generated 15.96 kWh. The most ever recorded on my system is on May 10th at 16.77 kWh.
My 21 panel 6.9kW array generated 42.97 kWh on June 21st. June is on track to be a record month for me (967 so far vs 1059 in Apr), but my record day was still back on Apr 28 at 48.74 kWh.