The phrase "reference temperature" refers to a standard or normal temperature used as a basis for comparison in scientific or technical measurements. Full definition
Sap also refers to just one set of monthly external reference temperatures for England and Wales, which has a very significant bearing on transmission and ventilation losses. (passivehouseplus.ie)
The Summary for Policy Makers at the beginning of AR5 defines «the past» by referencing temperatures to the global mean surface temperature averaged over 1985 - 2005. (judithcurry.com)
This provides a stable reference temperature structure for the fast feedback processes to operate and maintain the amounts of atmospheric water vapor and clouds at their quasi-equilibrium concentrations. (dotearth.blogs.nytimes.com)