Temperature is a fundamental quantity relevant to almost all spheres of human endeavour. It is measured and controlled in a very wide range of applications, for example in combustion (engines, heating), heat treatment of high value components, healthcare (fever screening), meteorology and climate monitoring. Measurement and control of industrial process temperature in particular is key to maximising product quality, optimising energy efficiency, reducing waste and minimising carbon dioxide and other harmful emissions. It is also essential for ensuring safety; an accurate measure of temperature minimises the risk of operating outside the required process envelope (for example in nuclear power generation). There are several settings in which recent innovations have brought about significant improvements in thermometry, and these are described in this themed issue. Also discussed in this issue is the assessment and optimisation of safety in lithium-ion batteries, which is also a very important topic given the ubiquity of those devices, and testing for corrosion in chemical process plants, again a widespread issue of great relevance to many practitioners.