Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. On Earth, most weather phenomena occur in the lowest level of the planet's atmosphere, the troposphere, just below the stratosphere. Weather refers to day-to-day temperature and precipitation activity, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth.
Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes, as most atmospheric heating is due to contact with the Earth's surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Earth's weather system is a chaotic system; as a result, small changes to one part of the system can grow to have large effects on the system as a whole. Human attempts to control the weather have occurred throughout history, and there is evidence that human activities such as agriculture and industry have modified weather patterns
Studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiter's Great Red Spot, is an anticyclonic storm known to have existed for at least 300 years. However, the weather is not limited to planetary bodies. A star's corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind. (Full article...)
A picture of a tree branch following a period of freezing rain. Freezing rain occurs when precipitation falls into an area where the temperature is above freezing (0º C, 32º F), melting any frozen precipitation. Closer to the ground, if the temperature drops back below freezing, the melted precipitation (now rain) becomes supercooled, and freezes instantly upon hitting an object. If freezing rain occurs for a long period of time, it can deposit a layer of ice on the ground and any objects which are not above the freezing point. This makes freezing rain an especially dangerous form of precipitation, as it can cause traffic accidents by making roads slippery, and can also cause trees and branches to fall, resulting in power outages and injuries to people who may be hit by falling trees or ice. The North American ice storm of 1998 was a long period of freezing rain which resulted in more than 30 deaths and billions of dollars in damage.