Michael J. Thompson served as the Director of the High Altitude Observatory at the National Center for Atmospheric Research (NCAR) in Boulder, olorado, where he was also a Senior Scientist. In September 2013, Michael became the Deputy Director and Chief Operating Officer of NCAR, enjoying a very close working relationship with Director Jim Hurrell. During this time, Michael oversaw an organisation conducting research in a range of fields, including his own topics of solar and stellar physics, as well as others such as atmospheric chemistry and climate science. At the same time, his son Robin was completing a PhD in mathematical epidemiology at the University of Cambridge, UK, after which he was awarded an independent Junior Research Fellowship at the University of Oxford. However, the work conducted at NCAR and Robin’s research have more overlap than might at first be expected. Here we present results from a collaboration that was set up following Michael’s untimely death in October 2018, between climate scientists (Jim Hurrell and Lantao Sun) and mathematical epidemiologists (Robin Thompson and Uri Obolski). Specifically, we propose a framework for studying the effect of climate variability and change on vector-borne disease risk. We introduce a new quantity—the Instantaneous Outbreak Risk (IOR)—which quantifies the risk posed by an invading pathogen accounting for the climatic conditions when that pathogen enters the population. We show how the IOR can be used to assess the threat from vector-borne diseases under a changing climate.