The grass could be conducting heat to the soil for storage and later emission back to space at night, or evaporative cooling. I'm guessing in general solar is

The grass could be conducting heat to the soil for storage and later emission back to space at night, or evaporative cooling. I'm guessing in general solar is a win for the environment, I'm a big fan of the tech, it's the only way most people can generate power right at home without obnoxious fumes or noise or something.... But I wouldn't be surprised if the temperature did change.