We examine the impact of temperature on mortality in Mexico using daily data over the period 1998-2017 and find that 3.8 percent of deaths in Mexico are caused by suboptimal temperature (26,000 every year). However, 92 percent of weather-related deaths are induced by cold (<12 degrees C) or mildly cold (12-20 degrees C) days and only 2 percent by outstandingly hot days (>32 degrees C). Furthermore, temperatures are twice as likely to kill people in the bottom half of the income distribution. Finally, we show causal evidence that the Seguro Popular, a universal health care policy, has saved at least 1,600 lives per year from cold weather since 2004.