Northwest China is experiencing escalating extreme temperature events, yet public awareness of their health risks remains suboptimal. This study conducted a cross-sectional survey of 1,000 urban and rural residents in Tianshui and Zhangye, Northwest China (January-March 2021), utilizing a three-stage sampling methodology and standardized questionnaires to evaluate health impacts and risk perceptions. Results revealed a significant disconnect between observed health effects and risk awareness. While extreme temperatures resulted in widespread health impacts – 97.5% reported discomfort, 20.4% sought outpatient care, and 8.3% required hospitalization – the average risk perception score was notably low (2.60/5.0). All perception dimensions scored below the neutral point (Concern: 2.98; Knowledge: 2.52; Fear: 2.33; Severity: 2.67; Controllability: 2.48), underscoring a “high impact, low perception” paradox. Rural residents demonstrated lower risk awareness than urban populations despite similar health impacts. Moreover, vulnerable groups (individuals aged ≥65, or with chronic illnesses) showed higher perception levels than younger, healthier individuals. These findings highlight an urgent imperative for improved risk communication strategies in Northwest China. The substantial health burden of extreme temperatures, coupled with insufficient public risk awareness, necessitates targeted policy interventions and community-based education programs to enhance climate adaptation.