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Measurements of atmospheric, land surface or sea temperature by satellites. Satellite temperature measurements are inferences of the temperature of the atmosphere at various altitudes as well as sea and land surface temperatures obtained from radiometric measurements by satellites. These measurements can be used to locate weather fronts, monitor the El Niño Southern Oscillation, determine the strength of tropical cyclones, study urban heat islands and monitor the global climate. Wildfires, volcanos, and industrial hot spots can also be found via thermal imaging from weather satellites. Weather satellites do not measure temperature directly. They measure radiances in various wavelength bands. Since 1978 microwave sounding units (MSUs) on National Oceanic and Atmospheric Administration polar orbiting satellites have measured the intensity of upwelling microwave radiation from atmospheric oxygen, which is related to the temperature of broad vertical layers of the atmosphere. Measurements of infrared radiation pertaining to sea surface temperature have been collected since 1967. Satellite datasets show that over the past four decades the troposphere has warmed and the stratosphere has cooled. Both of these trends are consistent with the influence of increasing atmospheric concentrations of greenhouse gases.

Satellites do not measure temperature directly. They measure radiances in various wavelength bands, which must then be mathematically inverted to obtain indirect inferences of temperature. The resulting temperature profiles depend on details of the methods that are used to obtain temperatures from radiances. As a result, different groups that have analyzed the satellite data have produced differing temperature datasets. The satellite time series is not homogeneous. It is constructed from a series of satellites with similar but not identical sensors. The sensors also deteriorate over time, and corrections are necessary for orbital drift and decay. Particularly large differences between reconstructed temperature series occur at the few times when there is little temporal overlap between successive satellites, making intercalibration difficult.

Infrared radiation can be used to measure both the temperature of the surface (using "window" wavelengths to which the atmosphere is transparent), and the temperature of the atmosphere (using wavelengths for which the atmosphere is not transparent, or measuring cloud top temperatures in infrared windows). Satellites used to retrieve surface temperatures via measurement of thermal infrared in general require cloud free conditions. Some of the instruments include the Advanced Very High Resolution Radiometer (AVHRR), Along Track Scanning Radiometers (AASTR), Visible Infrared Imaging Radiometer Suite (VIIRS), the Atmospheric Infrared Sounder (AIRS), and the ACE Fourier Transform Spectrometer (ACE‐FTS) on the Canadian SCISAT 1 satellite. Since 1982, satellites have been increasingly utilized to measure SST and have allowed its spatial and temporal variation to be viewed more fully. For example, changes in SST monitored via satellite have been used to document the progression of the El Niño Southern Oscillation since the 1970s. Over land the retrieval of temperature from radiances is harder, because of inhomogeneities in the surface. Studies have been conducted on the urban heat island effect via satellite imagery. By using the fractal technique, Weng, Q. et al. characterized the spatial pattern of urban heat island. Use of advanced very high resolution infrared satellite imagery can be used, in the absence of cloudiness, to detect density discontinuities (weather fronts) such as cold fronts at ground level. Using the Dvorak technique, infrared satellite imagery can be used to determine the temperature difference between the eye and the cloud top temperature of the central dense overcast of mature tropical cyclones to estimate their maximum sustained winds and their minimum central pressures. Along Track Scanning Radiometers aboard weather satellites are able to detect wildfires, which show up at night as pixels with a greater temperature than The Moderate Resolution Imaging Spectroradiometer aboard the Terra satellite can detect thermal hot spots associated with wildfires, volcanoes, and industrial hot spots. The Atmospheric Infrared Sounder on the Aqua satellite, launched in 2002, uses infrared detection to measure near surface temperature.

From 1979 to 2005 the microwave sounding units (MSUs) and since 1998 the Advanced Microwave Sounding Units on NOAA polar orbiting weather satellites have measured the intensity of upwelling microwave radiation from atmospheric oxygen. The intensity is proportional to the temperature of broad vertical layers of the atmosphere. Upwelling radiance is measured at different frequencies; these different frequency bands sample a different weighted range of the atmosphere. Figure 3 (right) shows the atmospheric levels sampled by different wavelength reconstructions from the satellite measurements, where TLS, TTS, and TTT represent three different wavelengths.

A different technique is used by the Aura spacecraft, the Microwave Limb Sounder, which measure microwave emission horizontally, rather than aiming at the nadir. Temperature measurements are also made by GPS radio occultation. This technique measures the refraction of the radio waves transmitted by GPS satellites as they propagate in the Earth's atmosphere, thus allowing vertical temperature and moisture profiles to be measured.

Planetary science missions also make temperature measurements on other planets and moons of the solar system, using both infrared techniques (typical of orbiter and flyby missions of planets with solid surfaces) and microwave techniques (more often used for planets with atmospheres). Infrared temperature measurement instruments used in planetary missions include surface temperature measurements taken by the Thermal Emission Spectrometer (TES) instrument on Mars Global Surveyor and the Diviner instrument on the Lunar Reconnaissance Orbiter; and atmospheric temperature measurements taken by the composite infrared spectrometer instrument on the NASA Cassini spacecraft. Microwave atmospheric temperature measurement instruments include the Microwave Radiometer on the Juno mission to Jupiter.