Most of the warming NOAA/NASA claim is occurring, is during the Arctic winter.
By averaging all temperatures equally, they ignore the fact that there is essentially no latent heat in the Arctic winter. There is little evaporation, melting or freezing of water at -15C, so tiny swings in heat content produce large swings in temperature. By contrast, the Arctic summer and lower latitudes require much larger changes in heat to produce equivalent temperature changes. Note in the graph below how stable temperatures are near the pole in summer. During the summer, huge amounts of heat are required to produce small changes in temperature.
By averaging all temperatures equally, Arctic winter warming massively skews the global surface temperature record to exaggerate warming. This is one primary reason for the massive divergence between accurate satellite temperatures and worthless surface temperatures.
The global surface temperature record is a farce. It needs to be abandoned, as NASA planned to do 27 years ago.