Rain. Wind. Cyclones. Weather might be thought of as the day-to-day outcome of the fact that we live in the lower part of a huge fluid which moves in complicated ways because it is heated in some places more than others, and which is also spinning with the Earth! British scientists at the Meteorological Office and in universities have studied this complicated fluid in various ways: some have focused on weather data – producing maps of patterns and trends, others have conducted ‘thought experiments’ and solved mathematical equations of ‘motion’, others have even photographed the behaviour of droplets in clouds. Since the 1950s, efforts to understand the atmosphere, and to forecast the weather, have been transformed by satellite remote sensing, computer modelling and international data sharing and cooperation. Nevertheless, theatmosphere is a ‘chaotic system’ and weather forecasts, whether they appear to be or not, are probabilistic – summaries of the most likely outcomes. The atmosphere can change in unlikely directions, producing un-forecast weather, prompting public criticism and, in the case of the Great Storm of 1987 in Britain, calls for the resignation of scientists.