This article explains why standard Retrieval-Augmented Generation (RAG) silently corrupts history in Financial Services by answering past questions with present-day truth. It introduces Temporal RAG: a regulator-defensible retrieval pattern that conditions every query on an explicit as_of timestamp and retrieves only from Point-in-Time (PIT) slices governed by SCD2 validity, precedence rules, and repair policies. Using concrete implementation patterns and audit reconstruction examples, it shows how to make LLM retrieval reproducible, evidential, and safe for complaints, remediation, AML, and conduct-risk use cases.