Accurate determination of dormancy release in temperate fruit trees is essential for understanding cultivar adaptation under climate change. This study evaluates the potential of male meiosis as a biological marker to determine endodormancy release in apricot (Prunus armeniaca L.), and examines how the choice of dormancy phenotyping method influences chilling requirement estimates and future suitability assessments. Chilling requirements were determined over three seasons for four cultivars (‘Flopria’, ‘Madrigal’, ‘Nelson’, and ‘Oscar’) in northeastern Spain, using two phenotyping methods: the shoot-forcing test and male meiosis as a dormancy biomarker. Results showed that the male meiosis method consistently estimated higher chilling requirements than the forcing test, with differences of approximately 10–15 Chill Portions (CP). Estimates based on male meiosis also showed lower interannual variability and a closer alignment with seasonal temperature patterns. Statistical analysis revealed that the magnitude and significance of these differences varied depending on the cultivar and chill model considered. To assess future adaptability, chill accumulation was projected using CMIP6 climate models under SSP2-4.5 and SSP5-8.5 scenarios for 2050 and 2085. Projections indicated that while the four cultivars are expected to remain largely adapted by 2050, late-century suitability differed markedly depending on the dormancy phenotyping method used, with some cultivar-scenario combinations falling below critical chill thresholds by 2085, particularly under SSP5-8.5 when chilling requirements were defined using male meiosis. These results show that dormancy phenotyping methodology strongly affects both chilling requirement estimation and climate-change risk assessment in apricot.