25 million fewer pints of milk delivered from UK farms in May and June heatwaves – new analysis

On 26 May 2026 milk deliveries fell nearly 4% below the preceding week’s average, equal to 3.2 million pints, with 8.3m fewer pints across the May heatwave as a whole. A fall of this scale during a heatwave is unprecedented in nineteen years of data — comparable in kind to the disruption previously seen only during extreme cold snaps like the ‘Beast from the East’. On 26 June 2026, milk deliveries fell 4.3%, equivalent to 3.3 million pints. Across the full nine-day June heatwave, the cumulative shortfall reached around 9.4 million litres, equivalent to 16.5 million pints. Across both heatwaves, the dip in deliveries was equivalent to 25 million pints of milk, roughly two pints for every child in the UK [2].

Tom Cantillon, Senior Analyst at the Energy and Climate Intelligence Unit(ECIU) said, "The May and June heatwaves look like the clearest signals yet that extreme heat is impacting the UK’s dairy industry. With climate change set to exacerbate heat stress in dairy cows into the future, the dairy sector and the refrigeration machinery needed to protect its products faces real risks in the face of ever more extreme heat. This is another example of climate change impacting the resilience of our food system with dairy one several products that along with beef, coffee and chocolate have been core drivers of food price inflation and in which climate change is playing a role [3].

“The only way to avoid temperatures getting ever more extreme is to bring balance back to the climate by reaching net zero emissions, but in the meantime adaptive measures like planting trees to provide shade to cows in fields can help and this then also absorbs carbon so reducing emissions in the atmosphere.” 

May typically sees peak milk production in the UK, with deliveries from farms up 2-4% on April, but May 2026 saw only a 0.08% increase. May 2026 was the third warmest on record in the UK [4], with a recent study by Met Office scientists finding that breaking the previous May temperature record has been made three times more likely by climate change [5]. The June heatwave saw a sustained fall in delivery volumes, with delivery volume drops hitting record levels compared to equivalent periods going back to 2008.

Dairy cows are sensitive to extreme heat, particularly where heatwaves fall early in the year and coincide with high humidity. The May heatwave had a peak Temperature Humidity Index score of 78.8 at Heathrow, at the threshold at which research associates milk production losses per cow of up to 20%. Other regions experienced similar midday THI levels, including: Shawbury (77.2), Exeter (77), Sennybridge (76.2) and Chivenor (75.2). Dairy deliveries are dependent on on-farm cooling and cold delivery chains functioning effectively, to ensure the safe transport of milk. In extreme heat on-farm cooling systems may be placed under additional strain increasing the likelihood of spoilage and rejected deliveries.

Ruth Grice, a dairy farmer from Leicestershire [6] said, "The heat in May had a real impact. The cows were hot and bothered and were obviously prioritising staying cool over producing milk. When we did the night checks they were standing around the water troughs for relief from the heat, whereas normally they would be quietly sleeping or ruminating. 

"It's not just the drop in milk production; heat also affects the cows' fertility, which is crucial for a dairy farm's viability.
 
"We are increasing shade by creating hedgerows and planting large native trees, especially in areas the cows prefer between midday and their afternoon milking. However, the long, drought-like conditions we increasingly see in summer make establishing new trees and hedges challenging.
 
"There are technological solutions like fans in the sheds, but they are very expensive to install and maintain. It seems bonkers to try solving climate problems with equipment that depends on more fossil fuel use. For us, working with nature has to be at the heart of our future."
 
Until this year, every significant weather-driven disruption in nineteen years of data was caused by extreme cold. The appearance of a heat event in the same category is not in itself a supply crisis [7], but it represents the first statistical signal that extreme heat may be joining extreme cold as a risk to the reliability of dairy supply. With climate change set to increase the frequency and severity of such events, the dairy sector may be seeing an early warning of the risks it faces.

Maddy Coupe, Policy Manager at the Cold Chain Federation said, “The recent heatwaves in the UK serve as both a reminder and warning that extreme heat is already impacting our food supply chains and will become an increasing threat in the years ahead. Dairy and milk products rely on cold chain storage, transport and distribution systems, to get them from farm gate to the end consumer.
 
“Businesses in the cold chain sector have robust plans and protocols for maintaining the cold chain during times of disruption, including extreme heat, with buffers built into the system to protect food safety and quality. However, a significant amount of the UK's cold chain infrastructure was not built for the 40°C temperatures we are increasingly experiencing, with around half of cold storage facilities over 20 years old. As temperatures continue to rise, these temperature-controlled systems have to work harder to maintain the safety, quality and availability of food products including milk and dairy”
 
The timing of the May heatwave is particularly significant because May is typically when the UK’s milk deliveries peak and comes at a time when dairy cows are less adapted to extreme heat compared to later in the summer. Climate projections suggest events like this will intensify. Research projects that, in the absence of adaptation measures, heat stress-related income losses for dairy farmers in the South West of England could reach £13.4 to £33.8 million by the end of the century.