The conventional mortgage emerges endogenously in a model of lifetime household consumption, with rates of mortgage default and prepayment-move outcomes increasing after exposure to high temperatures. Empirically we find that households treated to high-temperature: i) show elevated rates of default and prepayment, particularly in high-amenity locations that are vulnerable to sea-level rise risk, ii) are more likely to relocate conditional on prepayment, and iii) are more likely to migrate to cooler parts of the country. Localized high-temperature shocks seem to intensify latent household concerns regarding the longer-run costs of climate change, which then triggers adaptive relocation decisions.