Baseline Shift
See how much warmer or cooler one year was than another.
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How to explore
Choose two years. The charts show their annual and monthly temperature differences.
Choose two years
Use Year and Compare with. A positive difference means the first year was warmer.
Compare months
The monthly chart compares January with January, February with February, and so on. Open the table to see the numbers.
Try a different average
Change Average used in the charts. Both years move by the same amount, so the gap between them stays the same.
- Chart average
- The average temperature over the 30 years you choose. Warmer years appear above zero; cooler years appear below it.
- Global temperature
- An estimate for the world as a whole, using temperatures over land and at the sea surface.
Compare
two years.
See how much warmer or cooler one year was than another. Choose two years below.
NASA estimates · Data saved September 17, 2026
Above or below the comparison average
Above or below the comparison average
A positive number means 2025 was warmer; a negative number means cooler.
Compare two years
The line shows each year’s difference from the 1951–1980 average, in degrees Celsius (°C). Above zero is warmer; below is cooler.
Scroll sideways on small screens. With a keyboard, focus the chart and use the arrow keys.
● 2025■ 1980
The dashed connector joins your two years. The horizontal dashed line marks the comparison average.
2025 is 0.93 °C warmer than 1980 in these annual estimates.
Compare the same months
Compare January with January, February with February, and so on. Each value shows the difference from that month’s 1951–1980 average, in °C.
Scroll sideways on small screens. With a keyboard, focus the chart and use the arrow keys.
● Solid: 2025■ Dashed: 1980
Show monthly values and differences
| Month | 2025 | 1980 | 2025 minus 1980 |
|---|---|---|---|
| Jan | +1.38 °C | +0.30 °C | +1.08 °C |
| Feb | +1.26 °C | +0.39 °C | +0.87 °C |
| Mar | +1.37 °C | +0.29 °C | +1.08 °C |
| Apr | +1.25 °C | +0.30 °C | +0.95 °C |
| May | +1.08 °C | +0.35 °C | +0.73 °C |
| Jun | +1.07 °C | +0.20 °C | +0.87 °C |
| Jul | +1.02 °C | +0.22 °C | +0.80 °C |
| Aug | +1.18 °C | +0.18 °C | +1.00 °C |
| Sep | +1.25 °C | +0.20 °C | +1.05 °C |
| Oct | +1.19 °C | +0.13 °C | +1.06 °C |
| Nov | +1.21 °C | +0.30 °C | +0.91 °C |
| Dec | +1.06 °C | +0.21 °C | +0.85 °C |
Compare ten-year averages
Each bar shows a decade’s average compared with 1951–1980. Choose one to compare its first and last years in the charts above. The unfinished 2020s are left out.
Left means cooler than the comparison average; right means warmer. All bars use the same scale.
Why this exists
The question
Compare two years in NASA’s global temperature record, then look at their monthly differences.
What to try
Choose two years to compare.
Method and limits
About the data
I saved NASA’s GISTEMP v4 global Land-Ocean Temperature Index data on September 17, 2026, after finding it through Data.gov. It contains 146 complete years, 1880–2025. I kept each published annual value and all twelve months. None are missing or filled in. Incomplete 2026 is left out. This is not a copy of the data as it stood on the entry’s September 10 date.
NASA’s figures compare temperatures with the 1951–1980 average. I keep those values unchanged. For 1991–2020, I subtract the average of its 30 annual values from every annual value. Monthly figures use a separate average for each calendar month. Decade bars average ten years. The chart scales stay fixed.
Figures are rounded. NASA may revise them. The charts do not show uncertainty from measurements or gaps in observations. They cannot explain causes or local effects, or predict future temperatures. Neither comparison average is the pre-industrial average used for international temperature goals.
Data: GISTEMP Team (2026), GISS Surface Temperature Analysis v4, NASA GISS, accessed September 17, 2026. Uncertainty: Lenssen et al. (2024), A GISTEMPv4 observational uncertainty ensemble, doi:10.1029/2023JD040179.
Skills used
- Data analysis
- Information design
- Interaction design
- Visual design
- Accessibility
What the data shows
- In this record, 2025 was 0.93 °C warmer than 1980. Changing the comparison average leaves that difference unchanged.
- Compared with 1951–1980, 2025 was 1.19 °C warmer. Compared with 1991–2020, it was about 0.58 °C warmer. Both describe the same year.
- A newer comparison average can make the numbers smaller. It does not change how much temperatures rose.