Will UK buildings need air conditioning? What the climate projections say
Updated 23 October 2026 · SEO Dons Editorial
What do the Met Office projections say about UK summers?
The Met Office says UKCP18, its set of UK climate projections, "remains the recommended and validated national climate dataset", even as a new national climate service is developed. Its article on climate change in the UK, which is undated but refers to 2020, says that across the UK it expects "hotter and drier summers" and "more frequent and intense weather extremes". Compared with 1990, by 2070 it projects:
- summers between 1 and 6°C warmer, and up to 60% drier depending on the region;
- hot summer days between 4 and 7°C warmer;
- a chance of exceeding 30°C for two days or more that is sixteen times higher in the south.
The scenario matters. The Met Office says it bases these changes "on the RCP8.5 high emissions scenario", and that reducing emissions can avoid some of the changes. It also stresses that "projections deal in probability, rather than definite outcomes". These are projections, not forecasts, and a lower-emissions scenario gives a smaller change.
How hot has it already got?
The Met Office reports that summer 2026 was provisionally the warmest on record for the UK, at an average mean temperature of 16.5°C. England, Wales and Northern Ireland each broke their own records, while Scotland had its joint-sixth warmest summer. The country figures, against the 1991 to 2020 average, were:
| Nation | Summer 2026 mean temperature | Above average by |
|---|---|---|
| England | 18.2°C | 2.5°C |
| Wales | 16.9°C | 2.2°C |
| Scotland | 13.8°C | 1.0°C |
| Northern Ireland | 15.4°C | 1.4°C |
The season's peak was 38.2°C at Hartpury College on 13 August, and 54 Met Office stations broke their all-time daily maximum. The UK record remains 40.3°C at Coningsby, Lincolnshire, verified in July 2022, with national records of 37.1°C for Wales and 34.8°C for Scotland set in the same heatwave. A Met Office study published in June 2025 estimated "a 50-50 chance of seeing a 40°C day again in the next 12 years".
The Met Office also frames 2026 against warming levels. A summer of that warmth "would remain above average in a world around 2°C warmer than pre-industrial levels", and "would be close to average at a global warming level somewhere between 2.5°C and 3°C". It adds that this does not mean every future summer will resemble 2026, because natural variability continues.
What does it look like region by region?
The Met Office says 2026 had a "marked regional contrast, with the greatest temperature anomalies in southern England". The table below uses its August 2026 figures, an observed snapshot of one hot month and not a projection. Its regions do not match this site's pages, so neighbouring pages share a figure where the Met Office does not split them. Each region page on the locations directory has local detail.
| Region page | Nearest Met Office region | Average daily maximum, August 2026 | Above average by |
|---|---|---|---|
| London | Greater London (county figure) | 26.8°C | 3.9°C |
| South East | Southeastern and central south England | 26.0°C | 4.0°C |
| East of England | East Anglia | 25.3°C | 2.9°C |
| East Midlands | Midlands | 24.2°C | 3.3°C |
| West Midlands | Midlands | 24.2°C | 3.3°C |
| South West | Southwest England and south Wales | 23.5°C | 3.6°C |
| Yorkshire | Eastern and northeastern England | 22.1°C | 2.1°C |
| North East | Eastern and northeastern England | 22.1°C | 2.1°C |
| North West | Northwest England and north Wales | 21.0°C | 2.2°C |
| Wales | Covered by southwest England and south Wales, and northwest England and north Wales | 23.5°C and 21.0°C | 3.6°C and 2.2°C |
| Scotland | East, west and north Scotland | 18.2°C, 18.1°C and 16.4°C | 0.8°C, 0.6°C and 0.2°C |
The pattern is clear even from one month: the south and the Midlands ran furthest above average, and Scotland stayed close to it. Northern Ireland has no region page on this site; its summer 2026 mean was 15.4°C, as above. For the long-run view of cooling demand by place, see cooling and heating degree days by UK region and the hottest places in the UK. The Met Office's UKCP18 map tool lets you select English regions, Wales and Scotland and view projected temperature change for four time slices, so ask a designer which projection they used.
What does that mean over a plant's life?
Take an assumption purely for illustration: cooling plant that lasts 15 to 20 years. Plant commissioned in 2026 would then run to between 2041 and 2046. The Met Office's map tool presents UKCP18 results in time slices of 2020 to 2039, 2040 to 2059, 2060 to 2079 and 2080 to 2099, so such plant would span the first two. London's planning policy asks designers to use CIBSE's TM49 datasets "to ensure that all new development is designed for the climate it will experience over its design life".
Which buildings feel it first?
- Existing offices and shops. The Climate Change Committee found "no datasets" giving an up-to-date picture of overheating in the non-residential building stock, so no one can say precisely how many are affected. It does say towns and cities "will become increasingly hot". For offices, see office air conditioning.
- Schools. The Committee notes progress in planning and assessing overheating in key public buildings, "including prisons and schools". See school ventilation.
- Hospitals and care settings. The Committee says many existing hospitals already "struggle to operate effectively" in heatwaves. See healthcare ventilation.
- Server and comms rooms. Their heat comes from the equipment, and HSE notes that high temperatures can be "created by work activity" rather than the season, so the case does not rest on the climate. See server and comms room air conditioning.
Approved Document O sets overheating standards in England but applies to new residential buildings, so it is not the route for offices or shops.
Passive measures first: when does active cooling become realistic?
The London Plan sets the clearest official order. Major developments must show how they will reduce overheating and "reliance on air conditioning systems" in line with a six-step cooling hierarchy:
- reduce the amount of heat entering a building, through orientation, shading, high albedo materials, fenestration, insulation and green infrastructure;
- minimise internal heat generation through energy efficient design;
- manage the heat within the building through exposed internal thermal mass and high ceilings;
- provide passive ventilation;
- provide mechanical ventilation;
- provide active cooling systems.
The Plan says the hierarchy applies to major developments but its principles can be applied to minor ones, and that if active cooling is unavoidable it should be designed to reuse the waste heat it produces. For non-domestic buildings it points to CIBSE's TM52 overheating assessment. The cooling hierarchy guide explains how planning officers apply it.
Active cooling tends to become the realistic option when the load is internal and constant, when passive measures cannot hold the required conditions, or when occupants are vulnerable. Whether it pays is a separate question: is air conditioning worth it for a UK business sets out the method. Readers who want to explore a specific building can send an enquiry through the site's form, starting from the locations directory.
Sources
- Met Office, Climate change in the UK (undated, refers to 2020), UK Climate Projections (UKCP18) and Maps of climate projections over land, checked 22 October 2026.
- Met Office, Summer 2026 provisionally hottest on record for the UK (1 September 2026, updated 17 September 2026), checked 22 October 2026.
- Met Office, Deep Dive: What could UK summers feel like in the future? (9 September 2026), checked 22 October 2026.
- Met Office, August 2026 weather stats: A regional breakdown and A county breakdown (September 2026), checked 22 October 2026.
- Met Office, Record high temperatures verified (28 July 2022) and Met Office report details rising likelihood of UK hot days (18 June 2025), checked 22 October 2026.
- Climate Change Committee, Progress in adapting to climate change: 2025 report to Parliament (30 April 2025), checked 22 October 2026.
- Greater London Authority, The London Plan 2021, chapter 9, policy SI 4, checked 22 October 2026.
- GOV.UK (MHCLG), Overheating: Approved Document O, checked 22 October 2026.
- HSE, Temperature in the workplace, checked 22 October 2026.
Common questions
Are climate projections the same as forecasts?
No. The Met Office says projections deal in probability, rather than definite outcomes, and it uses ranges because even for a given level of emissions there is uncertainty in how the climate will respond. A projection is also tied to a scenario, so always ask which one a figure assumes.
Which emissions scenario should a designer use?
The Met Office provides probabilistic projections for four pathways, RCP2.6, RCP4.5, RCP6.0 and RCP8.5, and many of the figures in its UK article use RCP8.5, a high scenario. For overheating assessments, London's planning policy points designers to CIBSE's TM49 datasets and TM52. Ask the designer to state which scenario and weather file they used.
Does Approved Document O cover offices?
No. GOV.UK says Approved Document O applies to new residential buildings. The Climate Change Committee has also noted gaps in monitoring overheating in the existing non-residential stock.
Will Scottish buildings need air conditioning?
Scotland ran closest to its average in summer 2026, with a mean of 13.8°C, 1.0°C above the 1991 to 2020 average. Buildings there can still have heat from equipment or occupants that needs removing, so the answer depends on the load rather than the postcode.
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