Hypothalamic hypocretin (HCRT) neurons control wake-sleep behavior, cardiovascular system and body temperature, and their loss entails narcolepsy. Cardiovascular regulation results from the interplay between central autonomic commands (CAC) and the baroreflex. The cross-correlation function (CCF) between spontaneous fluctuations of heart period (HP) and blood pressure (BP) yields information on this interplay. We investigated whether HCRT neurons are required for appropriate autonomic control of HP at different ambient temperatures (Ta) and wake-sleep behaviors. Narcoleptic mice with genetic ablation of HCRT neurons (n=11) and wild-type controls (n=12) were implanted with a telemetric BP transducer and electrodes for discrimination of wake-sleep behaviors. The CCF between HP and BP was computed in each mouse at Ta of 25°C, 30°C, and 20°C in random order. Data were analyzed with 3-way analysis of variance and t-tests (significance at P < 0.05). CCF changes depended on an interaction effect between ambient temperature and the wake-sleep behaviors regardless of the presence of HCRT neurons. In both mouse strains during rapid-eye-movement sleep, CAC on the heart prevailed at 30°C whereas baroreflex control of HP prevailed at 20°C. These results demonstrate that ambient temperature modulates the integration between cardiovascular control mechanisms during the wake-sleep cycle; this modulation is independent of the activity of HCRT neurons.