Yes, Canadas Chambord Limestone can be used in exterior applications in very sunny climates. However, it is important to note that limestone is a natural material that can be affected by weathering over time, especially in very sunny and hot conditions. Therefore, it is important to ensure proper installation and maintenance to prevent any potential issues. Additionally, some finishes or sealers may be recommended for added protection. Consulting with a professional in the field is always recommended to ensure the best results.