One year can be cooler than the year before while many decades become warmer overall. A trend describes the longer pattern, not every step. This graph uses NASA global temperature estimates for 1980 to 2024. Values show differences from the 1951–1980 average, rather than the temperature outside one home.
Weather and climate · Discover & try
How can a warming trend contain cooler years?
Reading level 1 of 5 · EarlyChange
Word help
Anomaly
A difference from a specified reference average.
Trend
A persistent pattern across an interval, which may contain shorter fluctuations.
Running average
An average recalculated over successive groups of observations.
Watch · Try · Explain
See how it works
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Actual NASA GISTEMP v4 annual anomalies, 1980–2024; optional trailing averages are Nepedia calculations, not forecasts.
What to look for
- Read the 1951–1980 reference period.
- Compare annual dips with the multi-decade record.
- Distinguish our trailing mean from NASA LOWESS.
Explain what you noticed
A different 40-year record rises overall but its last year is cooler than the previous year. What follows?
Keep this idea: Year-to-year variation and a multi-decade trend describe different time scales.
Follow the sources
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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