Likely related to climate. Many airlines will send their unused planes (eg. 737Max8's) to the desert for longer stays where the temperatures are fairly stable and weather remains generally static.
Pictures of airplanes in the desert currently: https://samchui.com/2020/04/25/photograp...qnr3Xt7mUk
Pictures of airplanes in the desert currently: https://samchui.com/2020/04/25/photograp...qnr3Xt7mUk