Coldest Month?

Satellite Accuracy?

Temps. Up or Down?

Global Warming?

Accurate Space "Thermometers"

Stratosphere's Coldest Month

Measuring Temperature from Space

1998 Temperature Trends


Temperatures & Vorticity

Temperature Anomaly





Globally-Averaged Atmospheric Temperatures

lower strospheric temps

The figure above shows the monthly temperature deviations from a seasonally adjusted average for the lower stratosphere - Earth's atmosphere from 14 to 22 km (9 to 14 miles). Red is an increase in the temperature from the average, and blue is a decrease in temperature. The large increase in 1982 was caused by the volcanic eruption of El Chichon, and the increase in 1991 was caused by the eruption of Mt. Pinatubo in the Philippines. November 2000 was the coldest month on record for stratospheric temperatures. The long-term downward trend in lower stratospheric temperatures is believed to be the result of ozone depletion (primarily), and to a lesser extent the increase in carbon dioxide concentrations due to the burning of fossil fuels.

lower tropospheric temps chart

This chart shows the monthly temperature changes for the lower troposphere - Earth's atmosphere from the surface to 8 km, or 5 miles up. The temperature in this region is more strongly influenced by oceanic activity, particularly the "El Niño" and "La Niña" phenomena, which originate as changes in oceanic and atmospheric circulations in the tropical Pacific Ocean. The overall trend in the tropospheric data is now +0.08 deg. C/decade (through 2004). Click on the charts to get the numerical data.

Surface thermometer measurements indicate that the temperature of the Earth is warming at an average rate close to +0.20 deg. C/decade since 1979, while the satellite data shows a warming trend of about half of this. These differences are the basis for discussions over whether our knowledge of how the atmosphere works might be in error, since the warming aloft in the troposphere should be at least as strong as that observed at the surface. A scientific report on what this apparent discrepency between the satellite and surface data means in the context of global warming theory will be completed in 2005 as part of the U.S. Climate Change Science Program.

This page, updated approximately monthly, will continue to provide the latest temperature measurements of various layers of the Earth's atmosphere from space.

We have a Java-based tool that allows you to interact with the Global Temperature Variations Data Set. Using this tool you can examine temperature variations from average at single locations on the globe or you may look at region averaged values. You can examine atmospheric temperature features for both the lower troposphere and the lower stratosphere in either degrees Fahrenheit or degrees Celsius.

The data used were obtained by the National Oceanographic and Atmospheric Administration TIROS-N satellite, and interpreted by scientists Dr. Roy Spencer (University of Alabama at Huntsville) and Dr. John Christy (University of Alabama at Huntsville) at the Global Hydrology and Climate Center (GHCC), a cooperative laboratory involving NASA, the Alabama Space Science and Technology Alliance, and private industry.

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Author: Dr. Roy Spencer (
Responsible Official: Dr. Steven J. Goodman (
Page Curator: Diane Samuelson (

Last Updated: January, 2005