Re-establishing national sovereignty has been a major issue of political discourse since the collapse of Soviet hegemony in Central and Eastern Europe. As this paper argues, scientific practices of long-term prediction have played a crucial role in post-socialist state actors‘ attempts to claim temporal sovereignty - the power over time. The paper examines the practices of different governments since the early 1990s of devising scientifically-based political visions of a distant future of Poland, the country whose post-socialist path of state and economic reform has often been described as the model case of neoliberalism’s hegemony and its alleged temporal presentism. It analyses published, archival and oral sources related to governmental claims of holistic future-knowledge, focussing on their concepts of sovereignty, predictive methodologies, institutional and social infrastructures of knowledge production, and their role in public debate. While the claim to know the future in advance presented its author as sovereign over time, its post-socialist epistemologies and politics were highly ambivalent and contradictory to this performative effect.