Do you have a lot of solar cells in your neighborhood or city or state? Then welcome to the PVHI.
“Because there are still large uncertainties surrounding the potential for a PHVI effect, we examined the PVHI empirically with experiments that spanned three biomes. We found temperatures over a PV plant were regularly 3–4 °C warmer than wildlands at night, which is in direct contrast to other studies based on models that suggested that PV systems should decrease ambient temperatures.”
And then your region can buy more air conditioners to try and cool off the evening, which will then pump more warm moist air into the area, which will increase the night time temperatures even more and then ….
sunshine hours 
I commented on some blog once that the effect of PV panels was to absorb the energy from the Sun and instead of re-emitting it to space as would happen if it warmed the Earth’s surface, it was to ensure that much of it remained trapped in the terrestrial energy system, and was thus likely to have more effect than the amount of CO2 it was supposed to be saving.
Needless to say I was roundly rubbished, and one poster (Griff as I recollect) asserted that this was not a problem as we were already working on transparent solar panels to replace windows, so they wouldn’t trap any heat at all.
I didn’t see much point in responding to that.
TINSSAAFL = there is no such thing as a free lunch
We learned this as school age children by reasonable parents who could think logically and employ common sense. Then, for some odd reason, kids grow up and lose their minds to take government and uni research positions just so they can bludgeon the rest of the public with their baseless rhetoric.