Sustainability has emerged as an important topic in policy debates, necessitating urgent actions to guide societies towards a liveable future. However, bridging the gap between scientific research and policymaking remains a challenge. Green monitoring systems hold promise in translating scientific insights into actionable information for policy makers. Despite this potential, limited research explores how these systems benefit policymakers across the policy cycle. This study examines the design affordances of green monitoring systems and their realization through six semi-structured interviews with green monitors designers. The findings indicate that these systems primarily support the early policy cycle stages of agenda-setting and policy formulation, as well as the final evaluation stage. Three essential conditions for realizing these affordances were identified: integration into existing policy frameworks, clear ownership of indicators by policymakers, and enhanced capacity to interpret and utilize monitoring data effectively. These findings contribute to the development of effective green IS for governments.