Mosquito-borne diseases cause substantial mortality and morbidity worldwide. These impacts are widely predicted to increase as temperatures warm, since mosquito biology and disease ecology are strongly linked to environmental conditions. However, direct evidence linking these changes to mosquito-borne disease is rare, and the ecological mechanisms that may underpin such changes are poorly understood. I focus on West Nile virus (WNV), a mosquito-borne arbovirus infecting avian hosts, that can spill over into humans. Outbreaks of WNV are common in Africa, and Southern and Eastern Europe, with recent outbreaks reported in France and Spain. There has yet to be an outbreak in the UK, but there is current concern that passerine migratory bird species could introduce the disease northward. However, the question remains, if WNV is introduced in the UK, can the disease establish? I present a mechanistic environmentally-driven stage-structured host-vector mathematical model for predicting the seasonal dynamics of WNV in current and future climates in the UK. The model predicts that WNV is unlikely to establish in the foreseeable future, although climate change is likely to increase the risk, with only extreme climate predictions leading to possible WNV outbreaks.