With a global year-to-date temperature that is 2.05°F (1.14°C) above the 20th century average by NOAA’s reckoning — far warmer than this point last year — 2016 is poised to become the warmest year on record.
As these records pile up, they affect long-term temperature averages, or what can be confusingly referred to as “normal.”
From a meteorological standpoint, normal is the 30-year average temperature for a particular location. NOAA calculates a new normal at the end of each decade, and it is the standard for most meteorological applications, like when your local forecaster tells you how the daily temperature compares to normal.
The current normals are based on the average temperatures from 1981 to 2010. The next normals will be based on the period from 1991 to 2020.
As the planet has warmed from the increase in greenhouse gases in the atmosphere, those normals have have mostly risen. In an overwhelming majority of sites across the country, the current normals are higher than those from 30 years ago (1951-1980)