We examine the impact on mortality of co-exposure to hot temperatures and power outages using a county-level data set in the United States from 2015 to 2019. We find that each additional hour of power outage is associated with a 0.04% increase in monthly mortality rate. Furthermore, we show that the mortality effects of hot days are exacerbated by the co-occurrence of power outages, with each hour of power outage in a month increasing the harm from a hot day by 3%. Larger magnitudes of both of these effects are identified for longer and more widespread outages. We also show heterogeneity across climate regions in the estimated relationships, which is consistent with heavier reliance on technological adaptations to heat such as air conditioning in hotter climate regions. Taken together, our results suggest that the reliability of electricity grids serves as an important means of adaptation to high temperatures and climate change.
