Climate change and the increasing frequency of high temperature (HT) events are significant threats to global crop yields. To address this, a comprehensive understanding of how plants respond to heat shock (HS) is essential. Signaling pathways involving calcium (Ca²⁺), a versatile second messenger in plants, encode information through temporal and spatial variations in ion concentration. Ca²⁺ is detected by Ca²⁺-sensing effectors, including channels and binding proteins, which trigger specific cellular responses. At elevated temperatures, the cytosolic concentration of Ca²⁺ in plant cells increases rapidly, making Ca²⁺ signals the earliest response to HS.