Contribution (%) of each bioclimatic variable to the PCA analysis.

+Three categories (F1–F3) are used to analyze the 19 bioclimatic variables. Three main components and the percentage of explained variance are indicated for each category.*Variables used in the third analysis (selected because of being strictly drought-related variables).- Bold numbers: Variables with significant contribution in the definition of the respective component and pertinent for drought stress estimation.- Bold and italic numbers: Variables with significant contribution in the definition of the respective component but not conceptually pertinent for drought stress estimation.