This study examined the behavioral and physiological responses of dairy cows and native cattle to varying climatic conditions using the Comprehensive Climate Index (CCI). The experimental animals comprised 16 cows in total, with equal representation from two breeds: Holstein Friesian (HF; n = 8) and Anatolian Black (AB; n = 8). Over the course of one year (September 2019 to September 2020), wearable sensor technologies were used to continuously monitor hourly and daily patterns of physical activity (high-active, basic-active, not-active), eating, rumination, and ear temperature. Results indicated that HF cows generally displayed greater levels of active behavior, eating, and rumination, whereas AB cows spent more time in basic-active and not-active states. Both breeds exhibited increased activity and reduced rumination and resting time as thermal stress intensified across CCI categories. Feeding behavior was most prominent under moderate, thermoneutral conditions. Diurnal rhythms showed increased activity and ear temperatures during daylight hours, with rumination and resting behaviors concentrated at night, reflecting behavioral strategies for thermoregulation. Notably, AB cows maintained more stable behavioral patterns across climatic conditions, suggesting a higher level of heat adaptability. These findings highlight the importance of incorporating breed-specific climate resilience into dairy management strategies to safeguard welfare and productivity.