In this paper, we combine administrative data for Spain from 2010 to 2018 with meteorological data, to identify the effect of daily mean temperature on fertility. We demonstrate for Spain that hot days (≥25°C) decrease the total fertility rate nine months after exposure. Moreover, we do not observe any substantial heterogeneities in the effect of heat by mother's age, mother's educational attainment, sex of the newborn, climatic area, or air conditioning penetration. Our results suggest that climate change may be altering the seasonal distribution of births and affect fertility rates in a context with low fertility and rapid population ageing.
Keywords: Spain; TFR; fertility; heat; temperature.