<p>The Helankou petroglyphs are carved on feldspathic metagreywacke weathering crusts on both sides of the Helankou gorge. These petroglyphs are undergoing severe deterioration primarily attributed to deformation of weathering crusts induced by thermal cycling under solar radiation. However, the response patterns and mechanisms of feldspathic metagreywacke weathering crusts under solar radiation remain poorly understood. Monitoring of TBQ total radiation (total solar radiation), atmospheric temperature, and the temperature and strain of feldspathic metagreywacke weathering crusts with different orientations and dip angles is conducted at the study site. Extreme event analyses and finite element numerical simulations are performed, systematically revealing the response patterns and mechanisms of feldspathic metagreywacke weathering crusts under solar radiation. The results indicate that feldspathic metagreywacke weathering crusts with varying orientations and dip angles exhibit differential responses under solar radiation. There is a strong linear correlation between the temperature and the strain of the feldspathic metagreywacke weathering crusts. The highest temperature was found in feldspathic metagreywacke weathering crusts with a south orientation and dip angles of 15 ° on July 6, 2023, while it was identified in those with a south orientation and dip angles of 60 ° on December 21, 2023. The heterogeneous thermal stresses caused by the differences in spatial geometric attributes induce differential thermal expansion–contraction cycles, which ultimately result in spatially heterogeneous exfoliation in the feldspathic metagreywacke weathering crusts. These findings enhance our understanding of thermal degradation in metamorphic rocks under solar radiation and contribute to long-term durability prediction and conservation of such sites.</p>