Experts advise against painting homes when humidity levels exceed 80% to prevent potential damage. Optimal paint adhesion and longevity require specific moisture conditions within a building. High humidity interferes with the drying process, leading to issues like blistering, peeling, and mildew growth. The ideal humidity level for painting isn’t explicitly stated in the source, but exceeding 80% is flagged as problematic. Ignoring these recommendations can compromise the quality and durability of the paint job, necessitating costly repairs. Homeowners are encouraged to monitor humidity levels before undertaking painting projects to ensure successful results.