Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Increased summertime heat stress in the US


In the past half century, the mean summertime temperature in the United States has increased1,4, with nights warming more than days5,6. When humidity is high, hot weather can cause heat stress in humans. Here we show that the frequency of extreme heat-stress events in the United States, caused by extremely hot and humid days as well as by heatwaves lasting for several days, has increased over the period from 1949 to 1995.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1: Trends in the annual frequency of the daily-minimum apparent temperature exceeding local threshold values from 1949 to 1995.


  1. Hansen, J. & Lebedeff, S. Geophys. Res. Lett. 15, 323– 326 (1988).

    Google Scholar 

  2. Jones, P. D. Geophys. Res. Lett. 21, 1149– 1152 (1994).

    Google Scholar 

  3. Nicholls, N. et al. (Cambridge Univ. Press, 1996).

  4. Gaffen, D. J. & Ross, R. J. J. Clim. (in the press).

  5. Karl, T. R. et al. Bull. Am. Meteorol. Soc. 74, 1007– 1023 (1993).

    Google Scholar 

  6. Easterling, D. R. et al. Science 227, 364– 367 (1997).

    Google Scholar 

  7. Mearns, L. O., Katz, R. W. & Schneider, S. H. J. Clim. Appl. Meteorol. 23, 1601– 1613 (1984).

    Google Scholar 

  8. DeGaetano, A. T. J. Clim. 9, 1646– 1782 (1996).

    Google Scholar 

  9. Changnon, S. A., Kunkel, K. E. & Reinke, B. C. Bull. Am. Meteorol. Soc. 77, 1497– 1506 (1996).

    Google Scholar 

  10. Kalkstein, L. S. & Davis, R. E. Ann. Assoc. Am. Geogr. 79, 44– 64 (1989).

    Google Scholar 

  11. Steadman, R. G. J. Clim. Appl. Meteorol. 23, 1674– 1687 (1984).

    Google Scholar 

  12. Gallo, K. P., Owen, T. W., Easterling, D. R. & Jameson, P. F. JClim. (in the press).

  13. McMichael, A. J. Climate Change 1995: Impacts, Adaptations and Mitigation of Climate Change (Cambridge Univ. Press, 1996).

  14. Lanzante, J. R. Int. J. Climatol. 16, 1197– 1226 (1996).

    Google Scholar 

Download references

Author information

Authors and Affiliations


Supplementary information


Supplementary information is available on Nature's World-Wide Web site ( or as paper copy from the London editorial office of Nature.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Gaffen, D., Ross, R. Increased summertime heat stress in the US. Nature 396, 529–530 (1998).

Download citation

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing