CC BY 4.0Krumm, AlisaAlisaKrummRossi, SaraSaraRossiLeithner, FelicitasFelicitasLeithnerBrown, WilliWilliBrownTheobald, JillJillTheobaldFernandez Lopez, TrinidadTrinidadFernandez LopezScheibstock, PeterPeterScheibstock2025-12-222025-12-222025-11-25https://publica.fraunhofer.de/handle/publica/502479https://doi.org/10.24406/publica-690410.3389/frsc.2025.166103810.24406/publica-69042-s2.0-105024203532Cities are central to climate action, with the district scale serving as a promising level for implementing climate interventions. However, municipal administrations often face significant barriers in integrating mitigation and adaptation strategies due to siloed departmental structures that limit effective collaboration. This article examines how the City of Munster, Germany, developed a Transition Guideline to systematically integrate climate mitigation and adaptation for existing urban districts through co-creative processes within municipal administration. Using a qualitative mixed-methods approach, a baseline analysis revealed critical organizational barriers: fragmented interdepartmental communication, misaligned data structures, and absence of systematic guidance for transforming existing building stock at the district level. Building on these findings, the City of Munster adapted the Climate Proofing approach – a five-step iterative framework for integrated climate action – into a practical guideline tailored to local governance structures. The resulting Transition Guideline consolidates available climate data, tools, and resources through interactive checklists that guide practitioners through integrated planning cycles while embedding co-creation as a core governance principle. Key findings demonstrate that structured co-creative frameworks have the potential to overcome institutional silos, though persistent gaps remain in district-scale carbon accounting and political engagement. This research provides a replicable methodological approach for municipalities seeking to bridge the gap between ambitious climate targets and implementation capacity at the district scale.entrueadaptationcarbon accountingclimate changeclimate proofingco-creationdistrict level interventionsmitigationurban planningjournal article