Temperature extrema

Definition

A general term for temperature variations above (extreme heat) or below (extreme cold) normal conditions (IRDR Glossary).

Since climate varies regionally, the definition of an extreme temperature and its threshold will differ from location to location. In other words, an extreme value in one location may be within the normal range in a different location (WMO).

A simple method is to establish a specific threshold for temperature and extreme precipitation events and evaluate the extremes that occur over (or under) that given threshold. Another common mean of ascertaining thresholds is based on selecting the tail of distributions for temperature and precipitation.Statistical partitions such as by quartiles or percentiles of the distribution have provided a means for evaluating extremes (WMO).

Facts and figures

Heat waves

A period of marked unusual hot weather (maximum, minimum and daily average temperature) over a region persisting at least three consecutive days during the warm period of the year based on local (station-based) climatological conditions, with thermal conditions recorded above given thresholds. Heat waves differ from warm spells. Similar to heat waves, warm spells are defined as a persistent period of abnormal warm weather. A warm spell occurs at any time of the year, whereas heat waves can only occur in the warm season (WMO).

Cold waves

A period of marked and unusual cold weather characterized by a sharp and significant drop of air temperatures near the surface (maximum, minimum and daily average) over a large area and persisting below certain thresholds for at least two consecutive days during the cold season. “Cool spell” refers to persistently below-average temperature conditions occurring during the warm season (WMO).

UN-SPIDER Regional Support Offices with hazard-specific expertise

Related content on the Knowledge Portal

  • The Sentinel-6 Michael Freilich satellite was launched into orbit on November 21, 2020. The launch was a culminated European-American effort that involved organisations from both sides of the atlantic. The European Space Agency (ESA), the European Organisation for the Exploitation of Meterological Satellites (EUMETSAT), the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA) and the National Centre for Space Studes (CNES) all collaborated together to make the launch of Sentinel-6 Michael Freilich a reality.​ The Sentinel-6 Michael Freilich satellite is the first of the Sentinel-6 satellites. An identical satellite, Sentinel-6B will follow in 2025. At an altitude of 1336 km the Sentinel-6 Michael Freilich satellite will use instruments on board to provide highly accurate measurements of the sea level in an effort to combat...

    read more
    21/11/2020
  • MetOp-C is the third and last satellite of the MetOp series that forms the space segment of the EUMETSAT Polar System (EPS).
    MetOp (Meteorological Operational) is Europe's first polar-orbiting operational meteorological satellite. It is the European contribution to the Initial Joint Polar System (IJPS), a co-operative agreement between Eumetsat and the US National Oceanic and Atmospheric Administration (NOAA) to provide data for climate and environmental monitoring and improved weather forecasting.
    MetOp-A (launched on 19 October 2006), MetOp-B (launched on 17 September 2012) and MetOp-C (launched 7 November 2018) are in a lower polar orbit, at an altitude of 817 kilometres, to provide more detailed observations of the global atmosphere, oceans and continents. The three satellites will operate in unison for as long as Metop-A's available capacities bring benefits to users. NOAA still continues to operate its mid-afternoon orbit satellite service as part of the...

    read more
    07/11/2018
  • The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) mission measures the temperature of plants to better understand how much water plants need and how they respond to stress. ECOSTRESS is attached to the International Space Station (ISS) and collects data over the conterminous United States (CONUS) as well as key biomes and agricultural zones around the world and selected FLUXNET (http://fluxnet.fluxdata.org/about/) validation sites. A map of the acquisition coverage can be found on the ECOSTRESS website (https://ecostress.jpl.nasa.gov/science).

    29/06/2018
  • Carrying a suite of cutting-edge instruments, Sentinel-3 will measure systematically Earth’s oceans, land, ice and atmosphere to monitor and understand large-scale global dynamics. It will provide essential information in near-real time for ocean and weather forecasting.
    The mission is based on two identical satellites orbiting in constellation for optimum global coverage and data delivery. For example, with a swath width of 1270 km, the ocean and land colour instrument will provide global coverage every two days. Sentinel-3B was launched on 25 April 2018.
    With a focus towards our oceans, Sentinel-3 measures the temperature, colour and height of the sea surface as well as the thickness of sea ice. These measurements will be used, for example, to monitor changes in sea level, marine pollution and biological productivity.
    Over land, this innovative mission will provide a bigger picture by monitoring wildfires, mapping the way land is used, provide indices of...

    read more
    25/04/2018
  • GOES-17 (formerly GOES-S) is the second of the current generation of weather satellites operated by the National Oceanic and Atmospheric Administration (NOAA). The four satellites of the series (GOES-16, -17, -T, and -U) will extend the availability of the GOES (Geostationary Operational Environmental Satellite system) until 2036 for weather forecast and meteorology research. The satellite was built by Lockheed Martin, was based on the A2100A platform, and will have an expected useful life of 15 years (10 years operational after five years of standby as an on-orbit replacement).The satellite was launched on 1 March 2018 and reached geostationary orbit on 12 March 2018. In May 2018, during the satellite's testing phase after launch, a problem was discovered with its primary instrument, the Advanced Baseline Imager. GOES-17 became operational as GOES-West on 12 February 2019. GOES-17 is currently operating alongside GOES-15 but will...

    read more
    01/03/2018
  • The Sentinels are a fleet of satellites designed specifically to deliver the wealth of data and imagery that are central to the European Commission’s Copernicus programme.
    Sentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands for a new perspective of our land and vegetation. The combination of high resolution, novel spectral capabilities, a swath width of 290 km and frequent revisit times provides unprecedented views of Earth.
    The mission is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery. Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator. Sentinel-2B was launched on 7 March 2017.
    As well as monitoring plant growth, Sentinel-2 can be used to map changes in land cover and to monitor the world’s forests. It also provides information on pollution in lakes and...

    read more
    07/03/2017
  • GOES-16 currently serves as the operational geostationary weather satellite over the U.S. East coast. Later this year, GOES-17 will become operational as the GOES West satellite.

    Both belong to the GOES-R series focuses on the detection and observation of environmental phenomena that directly affect public safety. The satellites provide advanced imaging with increased spatial resolution and faster coverage for more accurate forecasts, real-time mapping of lightning activity, and improved monitoring of solar activity and space weather.

    The GOES-R Series is a four-satellite program (GOES-R/S/T/U) that will extend the availability of the operational GOES satellite system through 2036. 

    Instruments:
    ABI (Advanced Baseline Imager)
    GLM (Geostationary Lightning Mapper)
    EXIS (Extreme Ultraviolet and X-ray Irradiance Sensors)
    SUVI (Solar Ultraviolet Imager)
    MAG (Magnetometer)
    SEISS (Space Environment In-Situ Suite)

    read more
    19/11/2016
  • Himawari 9 is a Japanese weather satellite, the 9th of the Himawari geostationary weather satellite operated by the Japan Meteorological Agency.

    02/11/2016
  • Sentinel-1 is a two satellite constellation with the prime objectives of land and ocean monitoring. The goal of the mission is to provide C-Band Synthetic Aperture Radar (SAR) data continuity following the retirement of ERS-2 and the end of the Envisat mission.
    To accomplish this the satellites carry a C-SAR sensor, which offers medium and high resolution imaging in all weather conditiions. The C-SAR is capable of obtaining night imagery and detecting small movement on the ground, which makes it useful for land and sea monitoring.
    Sentinel-1 will work in a pre-programmed operation mode to avoid conflicts and to produce a consistent long-term data archive built for applications based on long time series.
    The mission benefits numerous services. For example, services that relate to the monitoring of Arctic sea-ice extent, routine sea-ice mapping, surveillance of the marine environment, including oil-spill monitoring and ship detection for maritime security,...

    read more
    25/04/2016
  • Carrying a suite of cutting-edge instruments, Sentinel-3 will measure systematically Earth’s oceans, land, ice and atmosphere to monitor and understand large-scale global dynamics. It will provide essential information in near-real time for ocean and weather forecasting.
    The mission is based on two identical satellites orbiting in constellation for optimum global coverage and data delivery. For example, with a swath width of 1270 km, the ocean and land colour instrument will provide global coverage every two days. Sentinel-3A was launched on 16 February 2016.
    With a focus towards our oceans, Sentinel-3 measures the temperature, colour and height of the sea surface as well as the thickness of sea ice. These measurements will be used, for example, to monitor changes in sea level, marine pollution and biological productivity.
    Over land, this innovative mission will provide a bigger picture by monitoring wildfires, mapping the way land is used, provide indices of...

    read more
    16/02/2016

Term Parents

UN-SPIDER Regional Support Offices with hazard-specific expertise