This paper presents the results of the Sixth Thermal Image Super-Resolution Challenge held within the Perception Beyond the Visible Spectrum (PBVS) workshop at CVPR 2025. The challenge maintains the same cross-spectral benchmark dataset as the previous year, consisting of 1000 thermal images each paired with corresponding high-resolution RGB images. Track 1 focuses on single thermal image superresolution, enhancing low-resolution infrared images by a factor of ×8, whereas Track 2 addresses guided thermal image super-resolution, performing super-resolution at scale factors of ×8 and ×16 by leveraging high-resolution RGB images as auxiliary inputs. The 2025 edition attracted increased participation, with 128 teams competing in Track 1 and 86 teams in Track 2. The paper describes methodologies employed by the top participating teams, emphasizing innovations in transformer-based and hybrid architectures, and provides a detailed comparative analysis of the results between the 2024 and 2025 challenges. This analysis reveals significant progress in thermal image reconstruction accuracy, showcasing notable advances achieved by the leading methodologies.