Mexican Terracotta can be used for exterior applications in rainy climates, but it requires proper care and maintenance. Terracotta is a porous material, which means it can absorb water. In very rainy climates, the constant exposure to moisture can cause terracotta to deteriorate and become damaged over time.

To ensure the longevity of Mexican Terracotta in a very rainy climate, here are some recommendations:

1. Sealant: Apply a high-quality sealant to the terracotta tiles or pottery. This will create a protective barrier and reduce the absorption of water. Reapply the sealant periodically as recommended by the manufacturer.

2. Proper Installation: Ensure that the terracotta is properly installed, with appropriate slope and drainage. This will help water run off the surface and minimize water retention.

3. Regular Cleaning: Regularly clean the terracotta surfaces to remove dirt, grime, and moss or algae buildup. Use a mild detergent and a soft brush, avoiding harsh chemicals or abrasive materials that can damage the terracotta.

4. Protective Measures: Consider using additional measures like awnings, overhangs, or patio covers to provide extra protection and minimize direct exposure to rain.

5. Repair and Maintenance: Regularly inspect the terracotta for any signs of damage or cracking. Promptly repair any issues to prevent further damage and ensure the longevity of the material.

By following these guidelines, Mexican Terracotta can be used effectively in exterior applications in very rainy climates while minimizing the risk of moisture-related damage.