This Approach Paper outlines the framework, methodology, and analytical pathways guiding the Independent Evaluation of the GCF's Approach to and Portfolio of Climate Information and Early Warning System Interventions (CIEWS). The document provides an overview of the global context for climate services, the growing risks posed by climate change, and the critical role of CIEWS in strengthening resilience and reducing disaster impacts. It presents the evaluation’s objectives, theory of change, and criteria for assessing the effectiveness, coherence, and impact of GCF investments in CIEWS.