This paper examines how physical climate exposure affects firm performance and global supply chains. We document that heat at supplier locations reduces the operating income of suppliers and their customers. Further, customers respond to perceived changes in suppliers’ exposure: when suppliers’ realized exposure exceeds ex ante expectations, customers are 7% more likely to terminate supplier relationships. Consistent with experience-based learning, this effect increases with signal strength and repetition and decreases with country-level climate adaptation. Subsequent replacement suppliers show a lower expected and realized but similar projected heat exposure. We find similar results for suppliers’ exposure to floods.