Global Surface Temperature Anomaly (NASA GISTEMP, 12-Month Average)

## What this measures

The average of the latest twelve monthly global surface temperature anomalies from NASA GISTEMP v4, relative to 1951–1980, in degrees Celsius. Palanor computes it only when all twelve months are published.

## Why it matters

Averaging over a year removes the seasonal noise and most of the month-to-month weather, leaving the warming trend and the multi-year swings of El Niño and La Niña.

## How to read it

Higher is warmer. The value for a month is the mean of that month and the eleven before it, so turning points appear late. A new record in this series is a new record for any 12-month period in the NASA record.

## What it does not say

It inherits every limit of the monthly series, including the 1951–1980 baseline, which is not the pre-industrial baseline used by the Paris Agreement. It is computed by Palanor, not published by NASA, and it moves when NASA revises past months.

## Source

Computed by Palanor from NASA Goddard Institute for Space Studies, GISS Surface Temperature Analysis version 4 (GLB.Ts+dSST), https://data.giss.nasa.gov/gistemp/. Cite: GISTEMP Team, GISTEMP v4, NASA GISS; and Lenssen, N. et al. (2024), Journal of Geophysical Research: Atmospheres. US federal data, public domain.