Mongolian pastoral nomads traditionally consume meat during the cold season and milk products during the warm season. Among these is airag (fermented mare's milk), and Mongolia is one of the few regions that retains such traditional food. Through the Mongolian meteorological network, this is the first survey on airag, targeting 2,045 herders. We compared airag production between households producing it and households in general. Results revealed intensive production in central Mongolia, but less in surrounding areas, except along the western border. High horse-density in the central steppes and forest steppes provides an eco-climatological explanation, but this density pattern cannot explain inadequate production in eastern areas. Thus, culture and ethnicity may account for airag's regional distribution.