The weather was much better during this period and so the panel temperatures behave as expected. The top temperature is much higher during the day, and falls once the sun goes down. During the night, both temperatures decrease until dawn, when the panels start picking up the solar energy and warming. The lower part of the panel has a smoother decrease in temperature because the hot water from the top of the tanks conducts its way down the pipe cross-section and adds heat to the water supply for the bottom of the panels.