• Alaka BasuAlaka Basu
      Alaka M. Basu is Professor, Development Sociology, Cornell University, and a member of the Guttmacher-Lancet Commission on Sexual and Reproductive Rights and Health
      Alessandro RosinaAlessandro Rosina
      Professor of Demography and Director, Center for Applied Statistics in Business and Economics, Università Cattolica del Sacro Cuore
      Andrea BrandoliniAndrea Brandolini
      Head of Statistical Analysis Directorate, Bank of Italy
      Bruno MasquelierBruno Masquelier
      Professor of Demography, University of Louvain, Belgium
      Cheikh MbackéCheikh Mbacké
      Associate Professor, Sociology department, Laval University
      Cinzia ContiCinzia Conti
      Researcher at Istat, Head of Unit on Foreign Presence and Social Dynamics
      Corrado BonifaziCorrado Bonifazi
      Director of the Institute for Research on Population and Social Policies, National Research Council, Rome Italy
      Ernestina CoastErnestina Coast
      Associate Professor of Population Studies, London School of Economics
      Wang FengFeng Wang
      Professor of Sociology at the University of California, Irvine, USA, and Professor at Fudan University, Shanghai, China fwang(at)
      Francesco BillariFrancesco Billari
      Professor of Sociology and Demography, University of Oxford
      Gilles PisonGilles Pison
      Professor at Museum National d'Histoire Naturelle and Director of Research at the French National Institute for Demographic Studies (INED) (Paris)
      Gustavo De SantisGustavo De Santis
      Professor of Demography, University of Florence, Italy
      Jacques VallinJacques Vallin
      Emeritus Research Director at INED, Paris; Honorary President of IUSSP
      John KnodelJohn Knodel
      Research Professor Emeritus, Population Studies Center, Institute for Social Research, University of Michigan (USA) and International staff, College of Populations Studies, Chulalongkorn University (Thailand)
      Letizia MencariniLetizia Mencarini
      Associate professor of Demography, Bocconi University - Dondena Centre for Research on Social Dynamics and Public Policy & Collegio Carlo Alberto; P.I. ERC P.I. ERC project n. 313617 (2013-2018) SWELLFER
      Letizia TanturriLetizia Tanturri
      Associate Professor of Demography, University of Padova, Italy
      Massimo livi BacciMassimo livi Bacci
      Emeritus Professor of Demography, University of Florence, Italy
      Monica Das GuptaMonica Das Gupta
      Research Professor of Sociology, University of Maryland, USA
      Paula Miranda-RibeiroPaula Miranda-Ribeiro
      Professor, Demography Department and Cedeplar, Universidade Federal de Minas Gerais, Brazil.
      Peter McDonaldPeter McDonald
      Professor of Demography in the Australian National University. Honorary President of IUSSP and winner of the Irene B. Taeuber Award
      Roberto ImpicciatoreRoberto Impicciatore
      Università di Bologna.
      Salvatore StrozzaSalvatore Strozza
      Professor of Demography, University Federico II, Naples (Italy)
      Stefano MolinaStefano Molina
      Senior Program Officer, Giovanni Agnelli Foundation, Italy
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    • N-IUSSP is a new IUSSP news magazine, which will disseminate scientific findings from demographic research carried out all over the world. The practical implications of current trends, the risks and potentialities of emerging situations, the pros and cons of specific laws are discussed in rigorous but plain language.

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Summertime, and the livin’ is easy … and longer
Vivre au soleil toute l’année : le secret d’une vie plus longue ?

Tina Ho, Andrew Noymer
Death rates in usa - old people running in the summer

“Summertime, and the livin’ is easy” — so begins one of the most famous American songs, Summertime from the Gershwin brothers’ Porgy and Bess. Is the living really easier in the summer? For demographers, this might be answered by looking not at living, but at dying. Specifically, are death rates lower in the summer than at other times of year? From this perspective, the answer is yes — in the United States and other temperate regions, the living is easier in the summertime.

Death rates in summer and winter

Our recent research (Ho and Noymer, 2017) looks at the question of what life expectancy would be if it was always summertime – and the answer is that women in the United States would have about one year more life expectancy, and men, about two-thirds of a year. Easier living, indeed, although the difference is not overwhelming. Rather than the four seasons, we divided the year into two “pseudoseasons”, to keep it simple: pseudowinter (November through April) and pseudosummer (May through October). We split mortality data for the United States into these pseudoseasons and calculated life expectancy for these periods instead of for calendar years. Figure 1 shows our results, as pseudosummer and pseudowinter life expectancy over time. Schermata 2018-02-25 alle 18.36.51

Mortality rates are lower in the summertime, yielding longer life expectancy. In fact, our findings indicate that winter mortality rates are higher by about ten percent, especially at ages 45 and above, the ages at which most deaths in the United States occur. If winter mortality rates are that much higher, why does life expectancy not differ by around ten percent – or about seven years – between the seasons? The answer lies in the nature of mortality at older ages: mortality rates rise steeply with age. The one-year probability of dying for a 70 year-old is about double that of a 60 year old; that for an 80 year-old is a little more than double that of a 70 year-old, and so on. A ten-percent difference in mortality rates has a marginal impact on this overall steep ladder of increasing mortality by age. So, life expectancy at levels typical of the United States is not drastically changed by the seasons, even though the summertime enjoys more lenient mortality.

Another way to think about the ten-percent lower mortality rates in the summer is in terms of age shifts. For people at about age 45 and up, death rates increase by age, so living in the summertime with its kinder mortality is just like being younger. Imagine the seasonal change like an age difference. In 2010, in United States, we found that for women at age 50, their “summer” age (in terms of mortality rates, compared to winter) is 49.4; at age 60, 59.3; at age 70, 69.1; at age 80, 79.0, and at age 90, 88.9. For men, the relationships were similar: 49.5; 59.3; 69.1; 78.9, and 88.7, respectively. Conceived as age shifts, these data are very telling. Yes, mortality is ten-percent lower in the summertime, but because death rates rise steeply by age, this is like being only a little younger. Therefore, the overall difference in life expectancy, while noticeable, is not enormous.

If I move to Florida will I live longer?

As a practical matter, what does this mean? If their goal is to live longer, should people move to warmer places with milder winters? All else being equal, yes, but with two major caveats. First, these effects are small for an individual, small enough that a person should just live where she wants to live. Second, there is much more to mortality than just temperature (Kalkstein, 2013). While tropical Hawaii is the U.S. state with longest life expectancy, Florida — also known for its warmth — only comes in 20th, while Minnesota, known for its severe winters, holds second place. What is more, not all the summer-winter effects are temperature-related. While causes of death such as thrombosis show an association with cold, the reasons for the seasonality of influenza and other respiratory viruses are not fully understood, and may be driven by the timing of the school year.

Nonetheless, when aggregated over millions of people moving to places with milder winters, the differences add up. Deschênes and Moretti (2009) estimate that population movements from the colder U.S. Northeast to the warmer Southwest “account for 4% to 7% of the total gains in life expectancy experienced by the U.S. population over the past thirty years”.

What about climate change? Our findings, based on data from 1959–2014, are hard to extrapolate. Hotter summers can bring more heat-related deaths, winter extremes still occur, and influenza persists, so unfortunately we do not regard our findings as predictive of a mortality silver lining to global climate change.

Fish are jumpin’, and the life expectancy is high

Demographers have a longstanding interest in the seasonality of mortality (Rau, 2006). In the United States and other temperate regions, winters see higher mortality than summers. The reasons are complex and include cold and the circulation of viruses (“the flu season”). Cardiovascular causes increase in the winter, which for some sub-causes like thrombosis are cold-related, and, more broadly, may be influenza-related (this is still not fully understood). Cancer mortality is not seasonal. All in all, the living is, in fact, a little easier in the summer if we’re talking about lower death rates. Universal influenza vaccines — ones that would not need to be re-administered every fall — are often described as a public health innovation that is desperately needed. Our work shows that the best-case scenario of their impact on life expectancy is about one year.


Deschênes, Olivier and Enrico Moretti. 2009. “Extreme weather events, mortality, and migration.” Review of Economics and Statistics 91(4):659–681.

Ho, Tina and Andrew Noymer. 2017. “Summertime and the livin’ is easy: Winter and summer pseudoseasonal life expectancy in the United States.Demographic Research 37(45):1445–1476.

Kalkstein, Adam J. 2013. “Regional similarities in seasonal mortality across the United States: An examination of 28 Metropolitan Statistical Areas.” PLoS One8(5):e63971.

Rau, Roland. 2006. Seasonality in human mortality: A demographic approach. No. 3 in Demographic Research Monographs, Springer, Berlin.


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