This document summarizes cattle performance and comfort under different environmental conditions. It provides data on January 2013 feedlot inventories by state and changes in market share of cattle on feed from 2012 to 2013. It discusses the challenges of cold stress, heat stress, and mud for cattle and how the environment affects energy requirements. Maps show cattle feeding regions and average annual precipitation and days below 0°C by location. Temperature ranges for cold stress and heat stress are identified, and the impacts of mud on cattle intake and performance are described.