A Fourth Heatwave and Winter Temperatures – Heating, Ventilation and Air Conditioning (HVAC) Matter More Than Ever
Estimated reading time 10 minutes
Throughout this summer we’ve seen “consistently above-average” temperatures with England reporting it’s warmest June on record.
Heatwaves Hit The UK
So far this year we’ve seen 4 heatwaves in the UK, when temperatures on three consecutive days surpass 25–28°C (77–82°F). The Met Office’s prediction of on-going climate change resulting in increased intensity and frequency of UK “warmer and wetter winters; hotter and drier summers and more frequent and intense weather extremes” is clearly true.
First Heatwave
On 18 June yellow heat-health alerts were issued by the UK Health Security Agency (UKHSA) for most of England and a temperature of 29.3°C (84.7°F) was recorded in St James's Park in London. Temperatures of 32°C (90.0°F) were recorded at Heathrow and Kew on 19 June.
The 20 June saw Scotland experience its hottest day of the year at 28.9°C (84.0°F) in Drumnadrochit, a village on the western shore of Loch Ness. On 21 June, a temperature of 33.2°C (91.8°F) was recorded in Charlwood in Surrey, England.
Second Heatwave
Further UKHSA amber heat-health alerts were issued for the East Midlands, East of England, London, South East and South West, with yellow alerts in place for the West Midlands and Yorkshire and the Humber on 26 June. On 27 June Santon Downham in Suffolk exceeded temperatures of 27°C (81°F).
Temperatures in London topped 31°C (88°F) on 29 June. In Yeovilton, a village in Somerset, temperatures reached 26.4°C (79.5°F). On 30 June temperatures were over 30°C (86°F) across a great deal of the UK, with a temperature of 33.1°C (91.6°F) recorded at Heathrow Airport. Both Wimbledon in South West London and Jersey, part of the Channel Islands, saw record temperatures of 32.3°C (90.1°F) and 33.4°C (92.1°F) respectively. On 1 July the highest temperature of the year was recorded at 35.8°C (96.4°F) in Faversham.
Third Heatwave
Amber heat-health alerts were issued by the UKHSA on 11 July for the East Midlands, East of England, London, South East, South West and West Midlands and a temperature of 34.7°C (94.5°F) was recorded in Astwood Bank near the Warwickshire - Worcestershire border. On 13 July, Ross-on-Wye, England hit temperatures of 31.1°C (88.0°F)
Fourth Heatwave
On 11 August another amber warning was issued for the East Midlands, West Midlands, East of England, London, and the South East. On 12 August, Northolt in London recorded the highest temperature at 33.4°C (92.1°F).
Temperature and Rainfall Extremes Becoming The Norm
The Guardian newspaper states there is “Profound concern’ as scientists say extreme heat ‘now the norm’ in UK.” The paper goes onto state that “Record-breaking extreme weather is the new norm in the UK, showing that the country is firmly in the grip of the climate crisis. The hottest days people endure have dramatically increased in frequency and severity, and periods of intense rain have also ramped up. Heatwaves and floods leading to deaths and costly damage are of “profound concern” for health, infrastructure and the functioning of society.” It further states that “the number of days with temperatures 5°C above the 1961-1990 average has doubled for the most recent decade 2015-2024 compared to 1961-1990. For 8°C above average the number has trebled and for 10°C it has quadrupled. The UK has also become 8% sunnier in the last decade. This shows how the hottest days we experience in the UK have increased in frequency dramatically in just a few decades.”
This is backed up by the Met Office who state that “record breaking and extreme weather has become increasingly commonplace in the UK as our climate has changed over the last few decades.
State of the UK Climate
The statements above are backed up by the State of the UK Climate report.
Each year the UK publishes an annual report with an up to date assessment of the UK climate. The latest State of the UK Climate report published in July 2025 shows that baselines are shifting and records are being broken more frequently than before.
Mike Kendon, Met Office Climate Scientist and Lead Author of the State of the UK Climate report says “Every year that goes by is another upward step on the warming trajectory our climate is on. Observations show that our climate in the UK is now notably different to what it was just a few decades ago. We are now seeing records being broken very frequently as we see temperature and rainfall extremes being the most affected by our changing climate. This pace of change and clustering of consecutive records is not a natural variation in our climate. Numerous studies have shown how human emissions of greenhouse gasses are warming the atmosphere and changing the weather we experience on the ground. Our climate in the UK is now different to what it was just a few decades ago, this is clear from our observations.”
Provisional statistics from the Met Office show that 2025 is shaping up to be one of the hottest summers on record. According to Emily Carlisle, a Met Office scientist “It’s looking like this summer [2025] is on track to be one of the warmest, if not ‘the’ warmest, since the series began in 1884. What’s striking is the consistency of the warmth. June and July were both well above average and even outside of heatwaves, temperatures have remained on the warmer side. This persistent warmth is driven by a combination of factors including dry ground from spring, high-pressure systems, and unusually warm seas around the UK. These conditions have created an environment where heat builds quickly and lingers. While we haven’t seen record-breaking highs, with 35.8°C the peak so far this year, the overall trend in consistently above-average temperatures is what matters.”
What Causes High Temperatures?
The Met Office say that there are several factors which have caused and continue to produce these persistent higher temperatures including “a dominant high-pressure system, dry spring soils reducing evaporative cooling, and a significant marine heatwave around the UK enhancing air temperatures.” They go onto say that climate change is also playing a part “with the UK warming at a rate of approximately 0.25°C per decade.”
It's Not Just About Higher Summer Temperatures, Winters Can be Impactful Too
It’s important to note it’s not just high summer temperatures that can cause issues. The Met Office and other bodies will tell you that winters are becoming warmer and wetter however warmer doesn’t necessarily translate into feeling warm. Although many parts of the UK have and will experience milder winters as yearly temperatures increase, temperatures can still reach minus figures in parts of the UK. In the winter of 2024 in Culdrose, Cornwall temperatures fell to -4.7oC and in Altnaharra, Sutherland temperatures plummeted to -12.5°C. In 2023 Braemar, Aberdeenshire hit a low of -17.3°C. Winters can still feel extremely cold when there is no “heating system” in place or where the heating system is poor and ineffectual.
In January this year temperatures fell below -8.1oC (17oF) in parts of Scotland. Elsewhere in England, plunging temperatures triggered an amber cold weather alert with temperatures dropping to -7.5oC in Shap, Cumbria, and -6.7oC at Bournemouth Airport.
Health Impacts Of Heat and Cold
Both heat and cold can significantly impact human health.
Heat
The human body regulates its core temperature of around 37.5°C through sweating and evaporation of that sweat. However, when temperatures are high the body can struggle to release this heat, which can lead to heat stress.
As the body starts to work harder to reduce the core temperature it can result in pushing the internal organs to and beyond their limits. The health effects of overheating include a heat rash, dehydration, dizziness, fainting, nausea, breathing difficulties, confusion, muscle cramps, headaches, tiredness, heat exhaustion and heart attacks. When temperatures reach over 40°C the result can be heatstroke, organ failure and death.
It's estimated that the June-July 2025 heatwave in London alone will have resulted in around 260 heat-related deaths. Statistics published by the UK Health Security Agency and Public Health England show that during the summers of 2023 and 2024 there were 2,295 and 1,311 heat-associated deaths respectively in England and in the summer of 2022 when England’s temperatures rose to above 40oC there was an estimated 2,985 heat-related excess deaths.
Cold
Cold also impacts human health. During cold temperatures the body must work to keep its internal core temperature at or around 37.5°C. When we start to get cold there is an increased risk of increased blood pressure as the body tries to conserve body heat by narrowing the blood vessels in the skin and extremities. This action results in increasing the pressure the heart must exert to pump blood through the body resulting in an increase in blood pressure. This in turn can lead to an increased risk of cardiovascular problems like heart attacks and strokes. The body’s response to cold can also lead to increased levels of a protein crucial for blood clotting called fibrinogen which makes the blood thicker and more viscous. This in turn can result in clotting leading to more cardiovascular issues such as heart attacks and strokes.
Cold weather can also lead to an increase in respiratory infections such as the flu and pneumonia. This is caused by a reduction in the immune response. If exposure to cold temperatures is prolonged it can lead to hypothermia. The cold can also exacerbate conditions like asthma and arthritis.
Mental health can also be impacted by cold weather. According to Sir Michael Marmot, the Institute of Health Equality Director “adults that experience prolonged cold temperatures at home double their risk of developing new mental health conditions, while the risk of exacerbating existing mental health issues triples. Meanwhile, an alarming 1 in 4 (28%) children that live in cold homes are at risk of multiple mental health symptoms, such as anxiety and depression. Physical discomfort from the cold, financial stress, social isolation and loneliness are all thought to contribute to declining mental health.“
According to E3G the UK has the “sixth-highest rate of excess winter deaths in Europe.” The article goes onto say that “over the last five years there has been an average of 32,000 excess winter deaths in the UK every year. Of these, 9,700 die due to a cold home.”
Pedro Guertler, co-author of the report from E3G said “The UK has one of the worst records on cold homes-related deaths in Europe and it is not only a public health tragedy, it is a national embarrassment. This epidemic is entirely preventable and E3G and NEA are calling on the UK Government to reinstate public capital investment in home energy efficiency to fix the cold homes crisis. As well as ending needless suffering and premature deaths, it would also address a wide range of national infrastructure priorities.”
Heating, Ventilation and Air Conditioning
It's clear that high and low temperatures are having a major impact across the UK and as such the need to be able to control indoor temperature is becoming a necessity. Having a Heating, Ventilation and Air Conditioning System can ensure consistent and controlled indoor temperatures throughout the hot summer and cold winter months.
Heating, Ventilation and Air Conditioning can provide the solution to controlling indoor temperature, keeping the inside warm when its cold outside and cool when its warm outside; it also controls the indoor humidity and purifies the air ensuring a comfortable home and work environment no matter the outside temperature. Technical innovation also means that air conditioning is an efficient and eco solution to heating and cooling your home and workplace.
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