One of the United Kingdom’s leading artificial intelligence supercomputers remained offline for over a week following a shutdown caused by last month’s record-breaking heatwave. The Dawn supercomputer, owned by the University of Cambridge and widely used by researchers in fields such as cancer and climate science, stopped functioning on June 27 due to a failure in the cooling system at the West Cambridge data centre.

The interruption affected multiple scientific projects, including the UK Cancer Vaccine AI Scientist & Supercomputing initiative led by the University of Oxford. “Dawn is offline. This means that our jobs are paused,” said Lennard Lee, director of the Oxford project. Lee noted that no data was lost and that ongoing work was expected to resume without repeating completed tasks.

The university attributed the shutdown to “technical issues during the hot weather” and reported that full cooling capacity had been restored, with access restoration expected to begin shortly after the incident. However, as of early July, the system remained offline.

The heatwave on June 27 saw temperatures reach 30 degrees Celsius inside the data centre, triggering the failure. Cooling for high-performance computing relies on air or liquid systems to dissipate the significant heat generated by processors. Legrand, the French company that owns USystems—the UK firm responsible for the cooling technology used at the facility—maintained that their equipment functioned as intended throughout the heat event.

In response to the incident, attention has turned to the resilience of supercomputing infrastructure amid increasingly frequent extreme weather conditions. Simon McIntosh-Smith, professor of high-performance computing at the University of Bristol, highlighted the importance of such facilities to UK research. “Supercomputers are vital resources,” he said. However, he acknowledged that designing systems to reliably operate in higher temperatures—potentially up to 50 degrees Celsius—would be substantially more expensive.

Dawn has played a critical role in advancing scientific efforts, including accelerating the development of personalised cancer vaccines and identifying cancerous markers in kidney scans. The British Antarctic Survey has also utilised the supercomputer for sea ice forecasting, while climate modellers have leveraged its capabilities to simulate environmental changes.

The West Cambridge data centre had previously flagged the need for “urgent improvements” to its cooling infrastructure, according to publicly available minutes from a December committee meeting. The university has not confirmed whether these upgrades were implemented prior to the heatwave.

Meanwhile, Jonathan Hirst from the University of Nottingham reported similar disruptions at a separate UK supercomputing facility used for chemistry research during the same heatwave, underscoring the wider impact of rising temperatures on critical scientific infrastructure.

The emergence of AI-focused supercomputers like Dawn and the University of Bristol’s Isambard-AI, which became fully operational last year, marks a significant advancement in the UK’s capacity to conduct complex data-intensive research. Lennard Lee noted that before these developments, such research was rarely feasible on this scale domestically.

This is not the first time extreme UK temperatures have affected computing. During the July 2022 heatwave, data centres operated by companies such as Google and Oracle also faced shutdowns as internal temperatures reached potentially damaging levels. The recent events underline ongoing challenges in maintaining reliable operation of advanced computing facilities amid changing climate conditions.