ABSTRACT This article examines the political work performed by the weather within contemporary big data predictive analytics. As a sociotechnical construction, the weather has long served as a predictive medium for forecasting human behaviour across historical contexts in order to reinforce settler colonial and imperial projects of spatial domination. Now, within twenty-first century big data systems, the weather has become a proxy for predicting human activity. Examining industrial materials from the predictive policing software HunchLab and the social media sentiment analysis platform Social Doppler, I argue that the weather proxy underwrites claims to prediction by collapsing the distinction between correlation and causation. Key here is how the proxy remediates the mechanism of impressibility that structured the weather as a racial technique for population management within nineteenth century statistical research. Through the weather proxy, big data programmes channel biopolitical frameworks of impressibility – or impressibility by proxy – in ways that causally bind individual behaviour to group-differentiated vulnerabilities of environmental exposure. At stake is how the weather proxy serves as a universal baseline condition for predicting population-level behaviour, which aims to mitigate accusations of racial bias by deferring to environmental conditions beyond human design. As a cultural construction tied to ubiquity, the weather thus is a rhetorical device that works to legitimate predictive analytics as impartial and universal while simultaneously effacing the violence that inheres within algorithmic technologies. Ultimately, by taking a comparative historical approach to the weather, I argue that we might better grasp the transformations in data science that underpin how ubiquity operates as a site of racial violence within contemporary surveillance systems.