Washing your car in direct midday summer sun is strongly discouraged. The combination of intense heat, UV radiation, and rapid water evaporation creates multiple risks: thermal shock to the clear coat, instant water spotting, premature drying of soap/shampoo (leaving residues and streaks), and increased chance of scratching because contaminants bake onto the surface. The ideal summer wash window is early morning (before 9 AM) or late afternoon/evening (after 5 PM) when the paint surface is cooler and the sun is lower. If you absolutely must wash at noon, work in the shade, keep the car cool with a pre-rinse, and dry each panel immediately.
