It is important to note that precipitation is also affected by air temperature. Cold air can't hold as much moisture. If deserts are colder, they are often drier. Solar panels, where they are set up, decrease the local temperature, which A. He et al.'s study suggests would slightly reduce cloudiness and precipitation. It only takes a 2 C temperature decrease to reduce precipitation by 20 % in desert regions. For these reasons, it was found that placing solar panels in a mixture of urban and desert regions minimizes many of the local environmental impacts of solar cells.
The moral of the story is that no matter what you do, the environment is effected. It is just a question of degrees and in what way things are affected.