Meteorology is the scientific study of weather effects and patterns, and it includes a great deal more than simple daily weather forecasting.
All parts of the world are inter-connected by weather patterns, by cycles of energy and matter, air and ocean currents and migrations of animals.
Most weather systems are metastable: they will continue while conditions remain the same, but small changes may switch them to a new metastable pattern.
Weather is metastable: world weather patterns can flip when a single wind or current pattern is disrupted, and the new pattern can be hard to switch back again.
Weather is driven by the flow of air around the world: that is to say, weather is driven by the wind patterns, as these also carry moisture and warmth.
Multi-year weather patterns include El Niņo which runs on about a four-year scale and the Pacific decadal oscillation which is on about a ten-year scale.
El Niņo is either a symptom or a cause of large-scale weather patterns over periods of several years, or quite possibly both, depending on how you look at it.
The Coriolis effect makes weather patterns move in roughly circular paths: in the south, winds go clockwise around a low, but counter-clockwise in the north.
Monsoon systems drive weather in Asia and northern Australia, bringing wet weather around June in Asia, and December on the southern side of the equator.
The monsoons of Asia and Australia are probably a relatively new phenomenon, driven by air circulation around the Himalayas, once they were uplifted.
Weather maps help in weather prediction, which is the art of extrapolating from the best available present data to an expected future outcome.
Ocean currents are interlinked and interactive, and form a delicate metastable pattern that pumps nutrients, warmth and weather patterns around the world.
The Conveyor is a worldwide ocean current that includes the Gulf Stream that keeps Europe warm. It is driven by the formation of sea ice in Arctic waters.
The main ocean currents of the world are driven by the formation of sea ice, which leaves cold, dense, salty water near the surface, from where it sinks.
Seasons are caused by the tilt of the earth on its axis, relative to its orbit, which leads to the solar radiation falling more on one hemisphere or the other.
In 1920, Milutin Milankovich suggested long term climatic cycles may be due to changes in the eccentricity of the Earth's orbit and in the Earth's obliquity.
Weather patterns travel from west to east because the earth rotates once a day. The weather is driven by ocean currents and their warmth or coolness.
Weather patterns are shaped by the so-called Coriolis force, the effect that makes wind leaving the equator move towards the east, generating eddies.
Alexander von Humboldt gave us isothermals, lines joining points of equal temperature. Plotting these globally showed the influence of geography on climate.
Air pressure changes from place to place, and in a single place, it varies with time. Isobars are lines on a map that join places with the same air pressure.
Air pollution may be trapped by an inversion layer, where dense air is trapped, especially in valleys, allowing an increase in local pollutant levels.
Weather shows extremes: floods occur when rivers spill over their banks, drought is usually driven by global effects, cyclones and tornadoes form over the sea.