Vaccines can lose potency when exposed to temperatures outside their specified storage range, and cold-chain failures may compromise immunization programs even if discovered only after delivery. Most monitoring systems react after a temperature threshold has already been crossed, limiting opportunities for re-cooling, rerouting, or shipment replacement before product integrity is threatened. To address this, a predictive machine learning model is proposed to estimate the probability of vaccine cold-chain failure before an excursion occurs, integrating streaming temperature data, packaging insulation characteristics, route conditions, and the shipment or container’s excursion history. Using a gradient-boosted classification framework applied to historical shipment records and continuously updated sensor feeds, the model considers features such as temperature trends, variability, packaging configuration, phase-change material properties, expected route exposure, and prior excursion severity. By identifying shipments whose thermal conditions are becoming unstable before formal failure thresholds are crossed, the model can support targeted interventions, including expedited transfer, additional cooling at hand-off points, or pre-release quality review. Predictive cold-chain analytics have the potential to shift vaccine logistics from retrospective excursion documentation to proactive risk management, reducing wastage, enhancing supply-chain resilience, and safeguarding the integrity of vaccination programs.