As an energy-free cooling technique, radiative cooling has garnered significant attention in the field of energy conservation. However, traditional radiative cooling films often possess static optical properties and their inherent opacity limits their applications in building such as windows. Therefore, there exists a requirement for passive radiative cooling films endowed with adjustable transmittance. Here we report the porous block copolymer films with self-adjustable optical transmittance and passive radiative cooling. In a result, the film exhibited a high solar reflectance (0.3–2.5 μm) of 96.9% and a high infrared emittance (8–13 μm) of 97.9%. Outdoor experiments demonstrated that the film surface temperature was 6.6 °C lower than ambient temperature, with a cooling power of 104.8 W·m^–2. In addition, the film’s transmittance can be regulated by altering the polarity of the post-processing solvent, providing an effective approach for regulating indoor light intensity and thermal balance, thereby enhancing the applicability of radiative cooling.

Passive radiative cooling is widely recognized as an environmentally sustainable method for achieving significant cooling effects. However, the mechanical properties and environmental adaptability of current radiative cooling materials are not sufficient to maintain high cooling performance in external environments. Here we reported an environment-adaptive phase-separation-porous fluorofilm for high-performance passive radiation cooling. Compared to the homogenous fluoro-porous network with limited scattering efficiencies, we modulated the porous structure of the fluorofilm to achieve a strong emissivity of 95.2% (8–13 μm) and a high reflectivity of 97.1% (0.3–2.5 μm). The fluorofilm demonstrates a temperature drop of 10.5 °C and an average cooling power of 81 W·m⁻² under a sunlight power of 770 W·m⁻². The high mechanical performance and environmental adaptability of fluorofilms are also exhibited. Considering its significant radiative cooling capability and robust environmental adaptability, the fluorofilm is expected to have a promising future in radiative temperature regulation.