Annual global and hemispheric surface temperatures
The global and hemispheric near-surface temperature series are created by geographical averaging of local deviations from the 1961-90 normals. These deviations are often called 'anomalies'. They are calculated from regular measurements of air temperature at fixed long-term land stations and from sea-surface temperatures measured from ships and buoys.
In the global and hemispheric plots, the final value for an incomplete year (green bar) is a preliminary value. Please note that until June this final value is not likely to be representative of the year as a whole. This is due to higher variability in the northern hemisphere during the winter period and the frequently different behaviour of later parts of the year.
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