Hydrogels, polymer networks that contain water as a solvent, have attracted significant interest due to distinct solid–liquid behavior, biocompatibility, and tunable optical and mechanical properties. Research focus and achievements in hydrogels have surged globally for decades. However, in practical applications, desirable properties are often lost due to dehydration under arid conditions and structural failure at subzero temperatures. This review critically evaluates strategies to enhance hydrogel stability across extreme environments through solvent engineering and molecular design. Potential interactions with the challenges in different design strategies are established. Synergistic combinations of these strategies yield hydrogels with prolonged dehydration resistance, freeze tolerance, and augmented functionality, such as mechanical resilience, self-healing, and ionic conductivity, making the hydrogels multifunctional for various applications. This review provides a roadmap for developing next-generation hydrogels capable of maintaining performance under arid and subzero conditions.