Yes, China Multicolor Slate can be used for exterior applications in very rainy climates. Slate is a natural stone that is known for its durability and water resistance. It is a popular choice for outdoor surfaces like walkways, patios, and pool surrounds because it can withstand exposure to rain, moisture, and extreme weather conditions. However, it is important to note that proper installation and sealing are crucial to ensure the long-term performance of the slate in rainy climates.