| Operation | Observed value − reference |
|---|---|
| Unit | Degrees Celsius or kelvin for differences |
| Requires | Comparable period and domain |
Definition and context
A temperature anomaly expresses a difference relative to an explicit reference. It should specify the variable, region, observed period, and reference period. A positive anomaly does not mean that all places or all days were warm.
In a hypothetical example, a monthly average of 11 °C compared with a monthly reference of 10 °C produces an anomaly of +1 °C. This operation does not provide information about highs, lows, or daily variability. When reading an actual figure, it is helpful to retain the chart caption and its source, because changing the reference or spatial domain changes the question. An anomaly is comparative information, not the absolute temperature of a place.
What we know and its limits
Introductory reference sheet. Properties and applications depend on measurement conditions; consult the sources before making comparisons.
Follow the evidence
The original sources for exploring this explanation and its limits.
- Global Temperature Anomalies · Graphing Tool
NOAA Climate.gov
Construction and consultation of land and ocean temperature anomalies. - About the data and methods
Copernicus Climate Change Service · ECMWF
Definitions of anomaly, domains, and time references.
Image credits
SciClue · AI-generated illustration (OpenAI) · Original source · Recurso editorial de SciClue · generado con IA