Reflection is made on the problems arising in the conservation of open-air sculptures owing to these monuments interacting constantly with environmental factors, involving processes that inevitably contribute to their deterioration. Knowledge of the materials used in their making, rigorous study to determine the source and quantification of damage and the carrying out of preliminary analyses and studies to determine the causes and development of alterations over time form a basic procedure that will guarantee the effectiveness of the intervention process, with the certainty that the higher the quality of analysis, the more accurate the diagnosis will be. Conservation and restoration work on pieces exhibited in the open air is more common owing to their constant deterioration. However, it is foreseen that these actions will become more regular as a result of the effects of climate change. Consequently, it is essential to evaluate the effectiveness of interventions in these types of treatments in detail.