<p>In addition to the international climate assessment reports developed by the Intergovernmental Panel on Climate Change, many countries and international organizations produce national or regional climate assessments. This study compares 21 exemplar climate assessments from nations and regions that span a wide range of socioeconomic and climate contexts. This comparison reports on similarities and differences in the assessments’ application, purpose, and governance; the scope, substance, and structure of assessment products; and the assessment development processes. Understanding these similarities and differences can inform future national and regional assessment developers. Furthermore, sharing processes, practices, and modes of presentation can be especially helpful to assessment developers facing resource or policy constraints. The approaches taken by several of the regional assessments–such as peer-to-peer learning, technical training–and collaborative data synthesis, demonstrate how pooled resources and knowledge sharing across nations can produce comprehensive and locally relevant assessments, as well as promote science diplomacy, all while building endogenous expertise. Targeted capacity building that supports knowledge sharing can also inspire innovation in how future assessments are developed, potentially leading to creative solutions for some of the political, social, or economic constraints faced by assessment developers.</p>