The paper delves into the relationship between modern architecture and climate issues, with a specific focus on a bioclimatic reinterpretation of the architectural endeavors of Eileen Gray (1879–1976), an Irish designer active in early 20th-century France. In contrast to the prevalent architectural research of the early 1900s, marked by the pursuit of universally applicable codes and driven by the futuristic enthusiasm for the Machine Age, Gray establishes an original design trajectory notable for both its theoretical thinking and practical application. Considering the contextual conditions in which she operates, Gray develops a design philosophy grounded in environmental principles that incorporates external natural elements as integral components of her architectural identity. Light and air, conceptualized by Gray as construction “materials”, harmonize with her architectures through meticulously designed systems of solar shading and natural ventilation. Despite the significance of the designer’s interest in environmental factors and climatic mediation devices, this aspect remains relatively underexplored in the literature, which is surprising given its clear role as a generative element for various technological and morphological design choices. Building upon the premise that attention to climatic issues is a constant in Gray’s research, the study extends its exploration to her lesser-known second villa, Tempe à Pailla in Castellar (1931–1935). After providing essential context about the intervention site and architectural conception, the paper delves into the environmental and typological principles governing the villa’s design, enriched by a critical examination of archival documentation. The considerations presented, partially derived from the outcomes of a doctoral research, aim to contribute an additional dimension to the diverse array of studies on Gray’s work, proposing a new interpretive framework with a focus on climatic aspects.