Weather is triggered by differences in air pressure (temperature and moisture) between one location and another. Global weather is highly dynamic and is determined by air currents in the atmosphere.
These differences in pressure and temperature may occur due to the sun's angle at a given point, which differs by latitude from the tropics. The farther away from the tropics, the lower the sun angle is, which results those areas to be cooler due to indirect sunlight. The huge temperature differences between polar and tropical air is what leads to the jet stream.
Weather refers to the state of the atmosphere of a particular place at a given time, in relation to such variables as temperature, moisture, barometric pressure and wind velocity. It is the degree of how hot or cold, calm or stormy, wet or dry, or cloudy or clear atmospheric conditions are in that area. Weather is essentially day-to-day temperature and precipitation. Generally, weather phenomena occur in the troposphere, just below the stratosphere. Weather is closely related to climate, but the two are different. Climate refers to the average weather conditions of a given place over a long period of time, often more than 30 years. Climatic information involves statistical weather information that reveals the actual weather, range and extremes.