DOI: 10.3886/e233268v1
title: Climate.gov Data Snapshots: Temperature - Global Yearly, Difference from Average

description: <b>Q: Where was the annual temperature warmer or cooler than usual?
</b><b>
 </b><br><b>A:</b> Colors
 show where average annual temperature was above or below its 1991-2020 
average. Blue areas experienced cooler-than-usual temperatures for the 
year while areas shown in red were warmer than usual. The darker the 
color, the larger the difference from the long-term average temperature.

 
 <br><b>Q: Where do these measurements come from?
</b><b>
 </b><br><b>A:</b> Weather
 stations on every continent record temperatures over land, and ocean 
surface temperatures come from measurements made by ships and buoys. 
NOAA scientists merge the readings from land and ocean into a single 
dataset. To calculate difference-from-average temperatures—also called 
temperature anomalies—scientists calculate the average annual 
temperature across hundreds of small regions, and then subtract each 
region’s annual average from 1991-2020. If the result is a positive 
number, the region was warmer than the long-term average. A negative 
result from the subtraction means the region was cooler than usual. To 
generate the source images, visualizers apply a mathematical filter to 
the results to produce a map that has smooth color transitions and no 
gaps.

 
 <br><b>Q: What do the colors mean?</b><b>
 </b><br><b>A:</b> Shades
 of red show where average annual temperature was warmer than the 
average from 1991–2020. Shades of blue show where the annual average was
 cooler than the long-term average. The darker the color, the larger the
 difference from average temperature. White and very light areas were 
close to their long-term average temperature. Gray areas near the North 
and South Poles show where no data are available.

 
 <br><b>Q: Why do these data matter?</b><b>
 </b><br><b>A:</b> Over
 time, these data give us a planet-wide picture of how climate varies 
over years and changes over decades. Each year, some areas are cooler 
than the long-term average and some areas are warmer. Though we don’t 
see an increase in temperature at every location every year, the 
long-term trend shows a growing portion of Earth’s surface is warmer 
than it was during the base period.

 
 <br><b>Q: How did you produce these snapshots?</b><b>
 </b><br><b>A:</b> Data
 Snapshots are derivatives of existing data products: to meet the needs 
of a broad audience, we present the source data in a simplified visual 
style. NOAA's Environmental Visualization Laboratory (NNVL) produces the
 source images for the Difference from Average Temperature – Yearly 
maps. To produce our images, we run a set of scripts that access the 
source images, re-project them into desired projections at various 
sizes, and output them with a custom color bar.

 
 
 <br><b>Additional information</b>
 Source images
 available through NOAA's Environmental Visualization Lab (NNVL) are 
interpolated from data originally provided by the National Center for 
Environmental Information (NCEI) - Weather and Climate. NNVL images are 
based on NOAA's Merged Land-Ocean Surface Temperature Analysis (MLOST).

 
 <br><b>References</b>
 
 NCEI Monthly Global Analysis<br>
NOAA View Temperature Anomaly<br>
Merged Land-Ocean Surface Temperature Analysis<br>
Global Surface Temperature Anomalies<br>
Climate at a Glance - Data Information
 <br>Source: https://www.climate.gov/maps-data/data-snapshots/data-source/temperature-global-yearly-difference-av...<br><br><br>This upload includes two additional files:<br>* Temperature - Global Yearly, Difference from Average _NOAA Climate.gov.pdf is a screenshot of the main Climate.gov site for these snapshots (https://www.climate.gov/maps-data/data-snapshots/data-source/temperature-global-yearly-difference-av...)<br>* Cimate_gov_ Data Snapshots.pdf is a screenshot of the data download page for the full-resolution files. <br><br><br>
description: Data is divided in to folders by image resolution -- full size (zip), small (png) and large (png). Occasionally there may be one image missing in a particular size but available in another size.<br><br>Data downloaded from climate.gov 6/17/2025.