The peaks have nothing to do with the temperature of the panels
What your describing is called "edge of cloud effect" which is when in
partly cloudy weather there is refraction/reflections caused by the clouds
and causes brief increases in the intensity of sun light the panels are
receiving
Its quite common to see 20-30% increases over clear conditions for short
bursts when the clouds move around , changing the intensity of the energy
received by the solar panels, this is the primary reason the NEC has a 125%
current handling requirement for the wiring in solar systems.
Temperature will degrade the output, about 0.08 volts per C increase in
temperature for a nominal 12 volt panel though we no nothing about the
system that stared this thread, or even how the drop was measured. I think
something other than the panels are the issue as the poster refers to what
is "stored" as the metric
Most likely is the "storage" can be down because the loads don't drain the
batteries and then the batteries can't take the charge from the available
solar input. In a battery based system, unlike Gridtie, you can only store
energy if there is a place to put it.
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