This is a fascinating subject and is always at the front of every pilot’s mind. Once you have learned about clouds and wind and weather you will never see the world in quite the same way again. The subject starts with a look at the International Standard Atmosphere (ISA) because all aircraft performance and instrument calibration is based on the incorrect assumption that the atmosphere conforms to a certain standard. Then we look at the basics of all cloud formation – water vapour and humidity, saturation, condensation, dew point and evaporation. As you learn to identify the different types of cloud and their natures you pick up the proper Latin names for them – which is very easy. Then we discuss thunderstorms, air masses, warm and cold fronts, atmospheric pressure and the five main pressure systems so you know what weather to expect if the met man tells you there is say a low pressure system approaching. Atmospheric stability and instability are the things that dictate whether you have a smooth or bumpy ride, and what sort of cloud to expect. Cloud cover, cloud base and visibility are of huge importance to aircraft – particularly for landing. We look at nasties like air-frame icing, fog, downdrafts. And finally you need to be able to understand the met codes that the weather office uses in things like met reports and forecasts, as well as special aviation things with names like METAR, TAF, SPECI, TTF, SIGMET, AIRMET, AIREP and Area Forecast. Sounds frightening, but it is actually easy once you get into it.