On the 24-25th February 2025 more than 70 world leading experts in thermometry gathered in Glasgow to take part in a Royal Society discussion meeting “The redefined kelvin: progress and prospects”.

The purpose of the meeting was to review the progress made in primary thermometry and to discuss and identify research priorities for the field in the next 5-10 years. The meeting had four technical sessions: “State of the art Primary Thermometry,” “New approaches to Temperature traceability,” “Quantum and photonic based thermometry” and “Practical impact on users of direct traceability to the kelvin.” There was also a poster session where 20 posters were presented. Very lively debate ensued after each paper and into the evening.

A record of the meeting will appear in a special edition of Philosophical Transactions of the Royal Society A which will be published later in 2025. The meeting was organised and led by Graham Machin of NPL.

Key relevant activities within ThermoSI were presented by NPL’s Jonathan Pearce, namely a) practical primary Johnson noise thermometry and b) establishing the SI-traceability framework for practical primary thermometry.