In this issue of Weather

This month's issue of Weather will be of particular interest to all those interested in measurement – not only of weather, but of rivers too. In Birmingham, Simon Bell, Dan Cornford and Lucy Bastin have been looking at the accuracy and precision of automatic weather stations. Their article ‘How good are citizen weather stations? Addressing a biased opinion’ on p. 75 compares temperature data from a Meteorological Monitoring System (Met Office) station with those from a range of relatively inexpensive sensors, often used by the public. In some cases, especially where the sensor has been left in direct sunshine, errors can be large, resulting in biases. Now that citizen data are being used by researchers and the Met Office, knowledge of these biases will be important. Many interesting investigations can be carried out by schools and researchers – not least weather differences on the small spatial scale. On p. 85, ‘Simple investigations of local microclimates using an affordable USB temperature logger’ by Geoff Jenkins demonstrates that this has become increasingly easy, using data loggers available for only a few pounds. If well exposed, these loggers can record reasonably accurate data over intervals between a few minutes and several hours. They could prove to be a useful resource to citizen observers, ensuring that data are available even during periods of absence. On p. 92, we turn to the observation of temperature differences in rivers flowing from the Derbyshire Peak. Little data are available to show how these temperatures change, following snowfall, rainfall or drought, but Robert Wilby, Matthew Johnson and Julia Toone help to rectify this in ‘Thermal shockwaves in an upland river’. This high density study covers the reasons for temperature variations in some detail and is a recommended read. Finally, Katy Mulqueen and Dave Schultz turn to the analysis of frontal systems for the North Atlantic and Europe in ‘Non‐classical extratropical cyclones on Met Office sea‐level pressure charts’ on p. 100. There has been considerable discussion of analysis charts in Weather over the years, reflecting the developments in our understanding. In particular, the authors discuss the reasons for the analysis of more than one front (be it warm or cold) in analysis charts, related to both the relatively simple Norwegian (‘Bergen’) model and the more recent Shapiro‐Keyser system. The issue is topped off, on p. 91, by contributors’ photographs of optical phenomena – always a calm and spectacular way to demonstrate the beauty of our science.