Yes, Indias Galaxy Green Slate can be used for exterior applications in very humid climates. Slate is a natural stone that is highly durable and resistant to water, making it suitable for humid conditions. It has a low water absorption rate, which helps to prevent moisture damage or cracking that can occur in humid environments. Additionally, slate is known for its thermal stability and can withstand temperature fluctuations in humid climates. However, it is always advisable to consult with a professional or supplier to ensure the specific slate variant is suitable for the intended exterior application and to follow proper installation and maintenance guidelines.