The term "hottest year" refers to a calendar year in which the average temperature for that entire year is higher than any other year. This measurement typically takes into account data from weather stations, satellite measurements and ground observations around the world to calculate an annual global temperature average. The hottest year on record is usually reported by meteorological organizations such as NASA's Goddard Institute for Space Studies or the National Oceanic and Atmospheric Administration (NOAA) in the United States. This information helps scientists understand long-term climate trends, including the impact of human activities on global warming.