China Grey Quartzite can generally be used for exterior applications in rainy climates. However, it is essential to note that the specific durability and performance of the quartzite may vary depending on the quality and characteristics of the material. It is advisable to choose a reputable supplier who can provide information about the quartzites suitability for exterior use in rainy climates. Additionally, proper sealing and maintenance measures should be taken to enhance the stones resistance to water absorption and potential damage.