Main points
- There were 22,272 deaths registered in Scotland in the four months of winter 2024/25 (December 2024 to March 2025). This is 1.3 per cent more than the previous winter.
- The number of winter deaths has fluctuated over the last ten years but has generally been increasing. This follows a decrease over the longer term.
- The seasonal increase in mortality of 2,704 for winter 2024/25 is higher than the previous winter (1,796), but it is not unusually high.
- There has been a long-term downward trend in the seasonal increase in mortality. In the 1950s and 60s, there was an average seasonal increase of over 5,200 deaths in winter, whereas over the most recent decade it has averaged around 2,700.
- The causes of death with the largest seasonal increase in winter 2024/25 were:
- influenza (530 additional deaths),
- dementia and Alzheimer’s disease (480 additional deaths),
- coronary (ischaemic) heart disease (300 additional deaths),
- chronic lower respiratory disease (250 additional deaths),
- other circulatory diseases (190 additional deaths),
- pneumonia (170 additional deaths),
- other respiratory system diseases (150 additional deaths),
- other mental and behavioural disorders and nervous system diseases (150 additional deaths), and
- cerebrovascular disease (120 additional deaths).
- The seasonal increase in influenza deaths (530 additional deaths) was the largest seasonal increase recorded for this cause in at least the past 15 years.
- Older age groups are consistently affected most by the seasonal increase in mortality in winter. In winter 2024/25, for people aged 85 and over there were 18 per cent more deaths compared to the months before and after winter. In the under 65 age group there were 9 per cent more deaths in winter.
Introduction
This publication provides statistics on mortality in Scotland during winter 2024/25. This includes trends since 1951/52, as well as breakdowns by age, sex, cause of death, areas of Scotland and other factors.
Winter months generally see more deaths than other times of the year. This report examines the seasonal increase in mortality in winter - the difference between deaths registered over winter (December to March) and the average number of deaths in the adjacent four-month periods (before and after). This definition is also used by other organisations like the Office for National Statistics (ONS) and the Northern Ireland Statistics and Research Agency.
The seasonal increase in mortality is calculated using data from death registration records. The latest year’s figures are provisional until the 2025 mortality data are finalised in summer 2026, but any revisions are usually small.
The seasonal increase in mortality in the winter is defined as the difference between the number of deaths registered in the four-month winter period (December to March, inclusive) and the average number of deaths in the two four-month periods which precede winter (August to November) and follow winter (April to July).
The seasonal increase represents the number of additional deaths in winter.
The Increased Winter Mortality Index (IWMI) is defined as the number of additional winter deaths divided by the average number of deaths in a four month non-winter period, expressed as a percentage. The IWMI accounts for differences in population size. It allows comparisons to be made between different sexes, age groups and geographical areas.
Winter mortality in Scotland
There were 22,272 deaths registered in Scotland in the four months of winter 2024/25 (December 2024 to March 2025). This is 1.3 per cent more than the previous winter.
It is generally expected that more deaths will be registered in the four winter months (December to March), than in either the four months before (August to November) or the four months after (April to July). There has been only one exception in 70 years: because of the coronavirus (COVID-19) pandemic, more deaths were registered from April 2020 to July 2020 than were registered in winter 2019/20 (December 2019 to March 2020).
The four month period before winter 2024/25 saw a small decrease in the number of deaths (2%), as did the four month period after winter (4%). The numbers of deaths in both of these periods were lower than they had been in the previous three years, but were high compared to the general trend.
Figure 1: Figures for the most recent years suggest a departure from the long-term downward trend in the number of deaths
Deaths registered in the Winter and in the preceding and following periods, Scotland, 1951/52 to 2024/25
Comparing the number of deaths in winter with the surrounding non-winter periods shows that the number of additional winter deaths can change from winter to winter and over time. The number of additional deaths in winter has been around the same average level for the past 25 years but has generally fallen over the long term. In the 1950s and 60s, there was an average seasonal increase in winter of over 5,200 deaths, whereas over the most recent decade it has averaged around 2,700. The steady fall in the average number of additional deaths in winter through the period from the 1950s to the 1980s has become a flatter trend.
Winter 2024/25 saw a seasonal increase in mortality of 2,704 compared to the surrounding non-winter periods. This is a larger increase than the previous winter (1,796), but it is not unusually high. There has been a lot of variation in the seasonal increase over the past decade with increases ranging from 550 to 4,813.
Figure 2: The number of additional deaths in winter has been around the same average level for the past 25 years but has generally fallen over the long term
Additional deaths in the winter, Scotland, 1951/52 to 2024/25
The Increased Winter Mortality Index
The seasonal increase in mortality can change substantially from winter to winter and over time but over the past 25 years the average number of additional deaths in winter has shown a relatively flat trend. The long-term trend has clearly been downward - in the 1950s and 60s.
The Increased Winter Mortality Index value for 2024/25 is 13.8 – the winter period had around 14% more deaths than the surrounding non-winter periods. The Index has had an average value of 14% over the past decade, whilst over the longer term it has fallen from an average winter increase of 27% in the 1950s and 60s to it’s current value of around half that level.
The seasonal increase in mortality in the winter by age-group
Older age groups are affected most by the seasonal increase in mortality in winter.
In winter 2024/25, for people aged 85 and over there were 18 per cent more deaths, compared to 9 per cent more for those aged under 65.
The figures fluctuate from year to year, but on the whole, the oldest age groups tend to have a greater seasonal increase in winter than the younger age groups.
Figure 3: Older people are affected most by the seasonal increase in mortality in winter
Increased Winter Mortality Index, by age-group. Scotland, 2012/2013 to 2024/25
The seasonal increase in mortality in the winter by sex
For most of the past 30 years, the number of additional deaths in winter – and the Increased Winter Mortality Index - has been greater for females than for males. This is largely explained by the fact that females, on average, live longer than males, and therefore account for a larger proportion of the population in older age groups. For females, in winter 2024/25 there were 15 per cent more deaths than in the surrounding non-winter periods and for males there were 13 percent more.
Figure 4: The seasonal increase in mortality in winter is greater for females than for males
Increased Winter Mortality Index by sex, Scotland, 1990/91 to 2024/25
The seasonal increase in mortality in the winter by deprivation
There is no clear evidence of any consistent difference in the seasonal increase in mortality in winter between the most deprived and least deprived parts of Scotland.
In winter 2024/25 the Increased Winter Mortality Index was greatest in quintile 4, at 18%. Quintile 4 is the second least deprived quintile. The two most deprived quintiles had an increase of 14% compared to other times of the year. As Figure 5 shows, the pattern has not been consistent over time.
Deprivation quintiles are based on the Scottish Index of Multiple Deprivation. This is a measure of how deprived an area is.
If an area is identified as ‘deprived’, this can relate to people having a low income but it can also mean fewer resources or opportunities.
A score is given to all of Scotland’s data zones based on multiple indicators of deprivation. The data zones are then ranked 1 to 6,976 based on their score. Subsequently, the rankings are split into 5 equally sized groups forming SIMD quintiles.
For this publication the quintiles were allocated according to the deceased’s usual place of residence.
Figure 5: There is no clear pattern linking deprivation with the seasonal increase in mortality
Increased Winter Mortality Index by SIMD quintile 2010/11 to 2024/25
The seasonal increase in mortality in the winter across areas in Scotland
There is no clear evidence of any consistent difference in the seasonal increase in mortality in winter across areas of Scotland. The Health Boards and Local Authority areas with the highest and lowest increased winter mortality indexes tend to fluctuate from year to year.
Tables 5 and 6 show the number of deaths in winter in each Local Authority and NHS Board area, along with the seasonal increases in each area.
The seasonal increase in mortality in the winter by cause of death
The causes of death with the largest seasonal increase in winter 2024/25 were:
- influenza (530 additional deaths),
- dementia and Alzheimer’s disease (480 additional deaths),
- coronary (ischaemic) heart disease (300 additional deaths),
- chronic lower respiratory disease (250 additional deaths),
- other circulatory diseases (190 additional deaths),
- pneumonia (170 additional deaths),
- other respiratory system diseases (150 additional deaths),
- other mental and behavioural disorders and nervous system diseases (150 additional deaths), and
- cerebrovascular disease (120 additional deaths).
The seasonal increase in influenza deaths (530 additional deaths) was the largest seasonal increase recorded for this cause in at least the past 15 years.
Figure 6: The seasonal increase in mortality is seen more acutely for specific causes of death
Seasonal Increase in Mortality in Winter 2024/25 (rounded) : main underlying causes
Very few deaths are directly due to cold weather (e.g. hypothermia); in each full calendar year since 2019 there have been fewer than 10 deaths from ‘exposure to excessive natural cold’.
The underlying cause of death is defined as the disease or injury which initiated the chain of morbid events leading directly to death, or the accident/act which produced the fatal injury. Statistics are normally produced on this basis because every death has just one underlying cause, and so will be counted only once.
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