Researchers have found that solar panels increase city temperature variations, causing cities to be hotter during the day and colder during the night. At the same time, these larger temperature swings result in higher wind speeds and potentially greater pollution.
Also, the paper casually mentions how rooftop solar reduces the cooling load of the building. What I didn’t see acknowledged was that that extra cooling load (presumably traditional A/C) on a building without rooftop solar moves the heat out of the building into… (drum roll), the surrounding environment. So… the heat still got to the surrounding environment, it just took a longer path to get there.