"The IDP is the principal statutory planning instrument for local governments in South Africa. In both cities, climate change interventions were initiated prior to the inclusion of climate change as a strategic priority in the IDP, which almost certainly facilitated that process. Although it is too soon to measure the impact of climate change mainstreaming with certainty, the experience of Cape Town and eThekwini provides lessons in the development of climate-compatible development processes at local levels. This brief reviews these lessons and highlights the importance of local capacity building, research, political support and decision-making in the pursuit of climate‑compatible development. Mainstreaming climate change has been described as a ‘holistic’ or ‘development‑first’ approach, whereby adaptation and mitigation objectives are included in development agendas; this approach has been defined as “the integration of policies and measures to address climate change into ongoing sectoral planning and management, so as to ensure the long-term viability and sustainability of sectoral and development investments.”