To address the urgent challenges of sustainability in our changing world, STEM education must evolve to integrate a stronger focus on socioenvironmental dimensions. This study examines how students in geomatics courses understand the nature of STEM (NoSTEM) in the context of meteorology and fire ecology—fields closely tied to sustainability. Using two validated mixed-method instruments comprising closed- and open-ended items, we assessed students’ comprehension across cognitive–epistemic and socio-institutional dimensions, framed within the family resemblance approach (FRA). Data collected from 44 students in meteorology and 57 in fire ecology were analyzed using descriptive statistics and phenomenographic methods. Our findings indicate that, while students demonstrate a stronger grasp of technical concepts, their understanding of socio-institutional implications is comparatively limited. These results highlight the need to align STEM education with sustainability education, emphasizing real-world applications and the integration of socio-institutional elements into the curriculum. Addressing these gaps is essential for preparing students to engage with complex sustainability challenges, such as those posed by climate change, resource management, and disaster mitigation. Future research should investigate long-term interdisciplinary educational strategies to foster a holistic understanding of NoSTEM and its role in promoting sustainable development.