Climate indicators · NASA GISS, GISTEMP v4
Global surface temperature
+1.18 °C
2025, against the 1951–1980 average. Average of the last ten years (2016–2025): +1.01 °C.
What it measures
How much warmer the air over land and the water at the sea surface are than in a fixed reference period. Thousands of weather stations, ships and buoys feed the record.
Why it matters
Temperature is the headline measure of global warming. Each tenth of a degree changes heat extremes, rainfall and the melting of ice.
Source and method
NASA GISS, GISTEMP v4. Annual means (January to December) as published. Other agencies use other reference periods, so their numbers differ by a fixed offset; we do not mix them.
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