Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and atmospheric physics), with a major focus on weather forecasting. An important branch of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects also include atmospheric interactions with large bodies of water. Meteorological phenomena are observable weather events that are explained by the science of meteorology. Meteorological phenomena are described and quantified by the variables of Earth’s atmosphere: temperature, air pressure, water vapour, mass flow, and the variations and interactions of these variables, and how they change over time. The Context of this study note is about the basics of the relevance and effects of weather in ship navigation.