International Journal of Biometeorology

, Volume 56, Issue 3, pp 421–428 | Cite as

UTCI—Why another thermal index?

  • Gerd Jendritzky
  • Richard de Dear
  • George Havenith
Special Issue (UTCI)


Existing procedures for the assessment of the thermal environment in the fields of public weather services, public health systems, precautionary planning, urban design, tourism and recreation and climate impact research exhibit significant shortcomings. This is most evident for simple (mostly two-parameter) indices, when comparing them to complete heat budget models developed since the 1960s. ISB Commission 6 took up the idea of developing a Universal Thermal Climate Index (UTCI) based on the most advanced multi-node model of thermoregulation representing progress in science within the last three to four decades, both in thermo-physiological and heat exchange theory. Creating the essential research synergies for the development of UTCI required pooling the resources of multidisciplinary experts in the fields of thermal physiology, mathematical modelling, occupational medicine, meteorological data handling (in particular radiation modelling) and application development in a network. It was possible to extend the expertise of ISB Commission 6 substantially by COST (a European programme promoting Cooperation in Science and Technology) Action 730 so that finally over 45 scientists from 23 countries (Australia, Canada, Israel, several Europe countries, New Zealand, and the United States) worked together. The work was performed under the umbrella of the WMO Commission on Climatology (CCl). After extensive evaluations, Fiala’s multi-node human physiology and thermal comfort model (FPC) was adopted for this study. The model was validated extensively, applying as yet unused data from other research groups, and extended for the purposes of the project. This model was coupled with a state-of-the-art clothing model taking into consideration behavioural adaptation of clothing insulation by the general urban population in response to actual environmental temperature. UTCI was then derived conceptually as an equivalent temperature (ET). Thus, for any combination of air temperature, wind, radiation, and humidity (stress), UTCI is defined as the isothermal air temperature of the reference condition that would elicit the same dynamic response (strain) of the physiological model. As UTCI is based on contemporary science its use will standardise applications in the major fields of human biometeorology, thus making research results comparable and physiologically relevant.


Outdoor climate Thermal assessment Index Thermal stress Thermo-physiology Model 



The UTCI project was performed within COST Action 730, funded by the European Union TRD Framework Programme and the International Society of Biometeorology Commission 6, under the umbrella of the World Meteorological Organization’s Commission on Climatology CCl.


  1. Blazejcyk K, Epstein Y, Jendritzky G, Staiger H, Tinz B (2011) Comparison of UTCI to selected thermal indices. Int J Biometeorol, this issueGoogle Scholar
  2. Blazejczyk K (1994) New climatological- and -physiological model of the human heat balance outdoor (MENEX) and its applications in bioclimatological studies in different scales. Zeszyty IgiPZ PAN 28:27–58Google Scholar
  3. Bröde P, Kampmann B, Havenith G, Jendritzky G (2008) Effiziente Berechnung des klimatischen Belastungs-Index UTCI. In: Gesellschaft für Arbeitswissenschaft (ed.): Produkt- und Produktions-Ergonomie - Aufgabe für Entwickler und Planer, GfA-Press, Dortmund, pp 271–274Google Scholar
  4. Bröde P, Fiala D, Blazejczyk K, Epstein Y, Holmér I, Jendritzky G, Kampmann B, Richards M, Rintamäki H, Shitzer A, Havenith G (2009a) Calculating UTCI Equivalent Temperature. In: Castellani JW, Endrusick TL (eds) Environmental Ergonomics XIII. University of Wollongong, Wollongong, pp 49–53Google Scholar
  5. Bröde P, Fiala D, Kampmann B, Havenith G, Jendritzky G (2009b) Der Klimaindex UTCI—Multivariate Analyse der Reaktion eines thermophysiologischen Simulationsmodells. In: Gesellschaft für Arbeitswissenschaft (ed.): Arbeit, Beschäftigungsfähigkeit und Produktivität im 21. Jahrhundert, GfA-Press, Dortmund, pp 705–708Google Scholar
  6. Bröde P, Fiala D, Blazejcyk K, Holmér I, Jendritzky G, Kampmann B, Tinz B, Havenith G (2011) Deriving the operational procedure for the Universal Thermal Climate Index UTCI. Int J Biometeorol, this issueGoogle Scholar
  7. Büttner K (1938) Physikalische Bioklimatologie. Probleme und Methoden. Akad. Verl. Ges, LeipzigGoogle Scholar
  8. COST UTCI (2004) Towards a Universal Thermal Climate Index UTCI for Assessing the Thermal Environment of the Human Being. MoU of COST Action 730. 17 pp
  9. De Dear R, Pickup J (2000) An Outdoor Thermal Environment Index (OUT_SET*) - Part II - Applications. In: De Dear R, Kalma J, Oke T, Auliciems A (eds.), Biometeorology and Urban Climatology at the Turn of the Millennium. Selected Papers from the Conference ICB-ICUC'99 (Sydney, 8–12 November 1999). WMO, Geneva, WCASP-50, pp 258–290Google Scholar
  10. Driscoll DM (1992) Thermal comfort indexes. Current uses and abuses. Nat Weather Digest 17(4):33–38Google Scholar
  11. Fanger PO (1970) Thermal comfort. Analysis and application in environment engineering. Danish Technical Press, CopenhagenGoogle Scholar
  12. Fiala D, Lomas KJ, Stohrer M (1999) A computer model of human thermoregulation for a wide range of environmental conditions: the passive system. J Appl Physiol 87(5):1957–1972Google Scholar
  13. Fiala D, Lomas KJ, Stohrer M (2001) Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions. Int J Biometeorol 45:143–159CrossRefGoogle Scholar
  14. Fiala D, Lomas KJ, Stohrer M (2003) First principles modeling of thermal sensation responses in steady-state and transient conditions. ASHRAE Transactions: Research Vol. 109, Part I, pp 179–186Google Scholar
  15. Fiala D, Lomas KJ, Stohrer M (2007) Dynamic simulation of human heat transfer and thermal comfort. In: Mekjavic IB, Kounalakis SN, Taylor NAS (eds) Environmental ergonomics XII. Biomed, Ljubljana, pp 513–515Google Scholar
  16. Fiala D, Psikuta A, Jendritzky G, Paulke S, Nelson DA, v Marken Lichtenbelt WD, Frijns AJH (2010) Physiological modelling for technical, clinical and research applications. Front Biosci S2:939–968CrossRefGoogle Scholar
  17. Fiala D, Havenith G, Bröde P, Kampmann B, Jendritzky G (2011) UTCI-Fiala multi-node model human heat transfer and thermal comfort. Int J Biometeorol, this issueGoogle Scholar
  18. Gagge AP, Fobelets AP, Berglund PE (1986) A standard predictive index of human response to the thermal environment. ASHRAE Trans 92:709–731Google Scholar
  19. Havenith G (2001) An individual model of human thermoregulation for the simulation of heat stress response. J Appl Physiol 90:1943–1954Google Scholar
  20. Havenith G (2005) Temperature regulation, heat balance and climatic stress. In: Kirch W, Menne B, Bertollini R (eds) Extreme weather events and public health responses. Springer, Heidelberg, pp 69–80Google Scholar
  21. Havenith G, Fiala D, Blazejcyk K, Richards M, Bröde P, Holmér I, Rintamäki H, Benshabat Y, Jendritzky G (2011) The UTCI clothing model. Int J Biometeorol, this issueGoogle Scholar
  22. Höppe P (1984) Die Energiebilanz des Menschen. München Universitäts Schriften, Fachbereich Physic, Wissenschaftliche Mitteilungen 49Google Scholar
  23. Höppe P (1999) The physiological equivalent temperature—a universal index for the biometeorological assessment of the thermal environment. Int J Biometeorol 43:71–75CrossRefGoogle Scholar
  24. Horikoshi T, Tsuchikawa T, Kurazumi Y, Matsubara N (1995) Mathematical expression of combined and separate effect of air temperature, humidity, air velocity and thermal radiation on thermal comfort. Arch Complex Environ Stud 7(3–4):9–12Google Scholar
  25. Horikoshi T, Einishi M, Tsuchikawa T, Imai H (1997) Geographical distribution and annual fluctuation of thermal environmental indices in Japan. Development of a new thermal environmental index for outdoors and its application. J Human–Environment System 1(1):87–92Google Scholar
  26. Huizenga C, Zhang H, Arens E (2001) A model of human physiology and comfort for assessing complex thermal environments. Build Environ 36:691–699CrossRefGoogle Scholar
  27. ISO 11079 (2007) Ergonomics of the thermal environment—determination and interpretation of cold stress when using required clothing insulation (IREQ) and local cooling effects. International Organisation for Standardisation, GenevaGoogle Scholar
  28. ISO 7243 (1989) Hot Environments; Estimation of the Heat Stress on Working Man, Based on the WBGT-Index (Wet Bulb Globe Temperature). International Organisation for Standardisation, GenevaGoogle Scholar
  29. ISO 7933 (2004) Ergonomics of the Thermal Environment - Analytical Determination and Interpretation of Heat Stress Using Calculation of the Predicted Heat Strain. International Organisation for Standardisation, GenevaGoogle Scholar
  30. Jendritzky G (1990) Bioklimatische Bewertungsgrundlage der Räume am Beispiel von mesoskaligen Bioklimakarten. In: Jendritzky G, Schirmer H, Menz G, Schmidt-Kessen W: Methode zur raumbezogenen Bewertung der thermischen Komponente im Bioklima des Menschen (Fortgeschriebenes Klima-Michel-Modell). Akad Raumforschung Landesplanung, Hannover. Beiträge 114:7–69Google Scholar
  31. Jendritzky G, de Dear R (2009) Adaptation and thermal environment. In: Ebi KL, Burton I, McGregor GR (eds.) Biometeorology for adaptation to climate variability and change. Biometeorology 1, Springer, Berlin, pp 9–32Google Scholar
  32. Jendritzky G, Nübler W (1981) A model analysing the urban thermal environment in physiologically significant terms. Arch Met Geoph Biokl B 29(4):313–326CrossRefGoogle Scholar
  33. Jendritzky G, Sönning W, Swantes HJ (1979) Ein objektives Bewertungsverfahren zur Beschreibung des thermischen Milieus in der Stadt- und Landschaftsplanung (“Klima-Michel-Modell”). Beiträge Akad. Raumforschung Landesplanung, 28, HannoverGoogle Scholar
  34. Jendritzky G, Maarouf A, Fiala D, Staiger H (2002) An update on the development of a Universal Thermal Climate Index. 15th Conf. Biomet. Aerobiol. and 16th ICB02, 27 Oct – 1 Nov 2002, Kansas City, AMS, pp 129–133Google Scholar
  35. Kampmann B, Bröde P (2009) Physiological responses to temperature and humidity compared with predictions of PHS and WBGT. In: Castellani JW, Endrusick TL (eds) Environmental ergonomics XIII. University of Wollongong, Wollongong, pp 54–58Google Scholar
  36. Kampmann B, Broede P, Fiala D (2011) Physiological responses to temperature and humidity compared to the assessment by UTCI, WGBT and PHS. Int J Biometeorol, this issueGoogle Scholar
  37. Konz S, Hwang C, Dhiman B, Duncan J, Masud A (1977) An experimental validation of mathematical simulation of human thermoregulation. Comput Biol Med 7:71–82CrossRefGoogle Scholar
  38. Koppe C, Kovats S, Jendritzky G, Menne B (2004) Heat-waves: risks and responses. World Health Organization. Health and Global Environmental Change, Series, No. 2, Copenhagen, DenmarkGoogle Scholar
  39. Landsberg HE (1972) The assessment of human bioclimate, a limited review of physical parameters. World Meteorological Organization, Technical Note No. 123, WMO-No. 331, GenevaGoogle Scholar
  40. Matzarakis A, Rutz F, Mayer H (2007) Modelling radiation fluxes in simple and complex environments—application of the RayMan model. Int J Biometeorol 51:323–334CrossRefGoogle Scholar
  41. Osczevski R, Bluestein M (2005) The new wind chill equivalent temperature chart. Bull Am Meteorol Soc 86(10):1453–1458CrossRefGoogle Scholar
  42. Parsons KC (2003) Human thermal environments: the effects of hot, moderate, and cold environments on human health, comfort and performance. Taylor & Francis, LondonGoogle Scholar
  43. Pickup J, de Dear R (2000) An Outdoor Thermal Comfort Index (OUT_SET*). Part I–The model and its assumptions. In: de Dear R, Kalma J, Oke T, Auliciems A (eds) Biometeorology and urban climatology at the turn of the millenium. Selected Papers from the Conference ICB-ICUC'99 (Sydney, 8–12 November 1999). WMO, Geneva, WCASP-50, pp 279–283Google Scholar
  44. Psikuta A (2009) Development of an ‘artificial human’ for clothing research. PhD Thesis, IESD, De Montfort University, Leicester, UKGoogle Scholar
  45. Psikuta A, Fiala D, Richards M (2007) Validation of the Fiala Model of Human Physiology and Comfort for COST 730. In: Mekjavic IB, Kounalakis SN, Taylor NAS (eds) Proceedings of the 12th International Conference on Environmental Ergonomics XII. Biomed, Ljubljana, p 516Google Scholar
  46. Psikuta A, Fiala D, Laschewski D, Jendritzky G, Richards M, Blazejcyk K, Mekjavic I, Rintamäki H, de Dear R, Havenith G (2011) Evaluation of Fiala multi-node thermo-physiological model for UTCI application. Int J Biometeorol, this issueGoogle Scholar
  47. Richards M, Havenith G (2007) Progress towards the final UTCI model. In: Mekjavic IB, Kounalakis SN, Taylor NAS (eds) Proceedings of the 12th International Conference on Environmental Ergonomics. 19–24 August 2007. Biomed, Ljubljana, Piran Slovenia, pp 521–524Google Scholar
  48. Shitzer A (2006) Wind-chill-equivalent temperatures: regarding the impact due to the variability of the environmental convective heat transfer coefficient. Int J Biometeorol 50(4):224–232CrossRefGoogle Scholar
  49. Shitzer A, De Dear R (2006) Inconsistencies in the “new” wind chill chart at low wind speeds. J Appl Meteorol Climatol 45:787–790Google Scholar
  50. Shitzer A, Tikuisis P (2011) Advances, shortcomings, and recommendations for wind chill estimation. Int J Biometeorol, this issueGoogle Scholar
  51. Staiger H, Bucher K, Jendritzky G (1997) Gefühlte Temperatur. Die physiologisch gerechte Bewertung von Wärmebelastung und Kältestress beim Aufenthalt im Freien in der Maßzahl Grad Celsius. Ann Meteorol Deutscher Wetterdienst, Offenbach 33:100–107Google Scholar
  52. Steadman RG (1984) A universal scale of apparent temperature. J Climate Appl Meteorol 23:1674–1687CrossRefGoogle Scholar
  53. Steadman RG (1994) Norms of apparent temperature in Australia. Aust Met Mag 43:1–16Google Scholar
  54. Stolwijk JAJ (1971) A mathematical model of physiological temperature regulation in man. NASA contractor report, NASA CR-1855, Washington DCGoogle Scholar
  55. Tanabe SI, Kobayashi K, Nakano J, Ozeki Y, Konishi M (2002) Evaluation of thermal comfort using combined multi-node thermoregulation (65MN) and radiation models and computational fluid dynamics (CFD). Energ Buildings 34:637–646CrossRefGoogle Scholar
  56. Tikuisis P, Osczevski RJ (2002) Dynamic model of facial cooling. J Appl Meteor 41:1241–1246CrossRefGoogle Scholar
  57. Tikuisis P, Osczevski RJ (2003) Facial cooling during cold air exposure. BAMS July 2003:927–934CrossRefGoogle Scholar
  58. VDI (2008) Environmental meteorology. Methods for the human biometeorological evaluation of climate and air quality for urban and regional planning. Verein Deutscher Ingenieure VDI. Part I: Climate. Beuth, BerlinGoogle Scholar
  59. Weihs P, Staiger H, Tinz B, Batchvarova E, Rieder H, Bröde P, Vuillemier L, Jendritzky G (2011) The uncertainty of UTCI due to uncertainties in the determination of radiation fluxes derived from measured and observed meteorological data. Int J Biometeorol, this issueGoogle Scholar
  60. Wissler EH (1985) Mathematical simulation of human thermal behavior using whole body models. In: Shitzer A, Eberhart RC (eds) Heat transfer in medicine and biology—analysis and applications. Plenum, New York, pp 325–373Google Scholar

Copyright information

© ISB 2011

Authors and Affiliations

  • Gerd Jendritzky
    • 1
  • Richard de Dear
    • 2
  • George Havenith
    • 3
  1. 1.Meteorological InstituteUniversity of FreiburgFreiburgGermany
  2. 2.Faculty of Architecture, Design & PlanningThe University of SydneySydneyAustralia
  3. 3.Loughborough Design School, Environmental Ergonomics Research CentreLoughborough UniversityLoughboroughUK

Personalised recommendations