Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather generally refers to day-to-day temperature and precipitation activity, whereas climate is the term for the average atmospheric conditions over longer periods of time. When used without qualification, "weather" is understood to be the weather of Earth.

Weather is driven by air pressure (temperature and moisture) differences between one place and another. These pressure and temperature differences can occur due to the sun angle at any particular spot, which varies by latitude from the tropics. The strong temperature contrast between polar and tropical air gives rise to the jet stream. Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow. Because the Earth's axis is tilted relative to its orbital plane, sunlight is incident at different angles at different times of the year. On Earth's surface, temperatures usually range ±40 °C (100 °F to −40 °F) annually. Over thousands of years, changes in Earth's orbit affect the amount and distribution of solar energy received by the Earth and influence long-term climate and global climate change.

Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes due to differences in compressional heating. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. The atmosphere is a chaotic system, so 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 human history, and there is evidence that human activity such as agriculture and industry has inadvertently 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, 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.

Read more about Weather:  Cause, Shaping The Planet Earth, Forecasting, Modification, Extremes On Earth, Extraterrestrial Within The Solar System, Space Weather

Other articles related to "weather":

WCCB - Digital Television - Digital Channels
... Until March 1, 2011, WCCB carried FOX Charlotte Weather on its third digital subchannel, which provided NOAA Weather Radio feeds from Spencer Mountain, Columbia ... Me-TV was scheduled to replace FOX Charlotte Weather on February 1, 2011, but was delayed by one month due to contractual issues ... FOX Charlotte Weather remains available through WCCB's mobile DTV service, and the Spencer Mountain and Rock Hill NOAA feeds were retained on the Me-TV ...
WTVT - News Operation - Weather Coverage
... WTVT's weather team is the most experienced weather team in the State of Florida, with over 115 years of combined experience, with most of that experience spent at Channel 13 forecasting tropical ... was the first TV news station in Florida to use radar in its weather presentation, and has made many advancements with the technology ... WTVT was also one of the first to use computer graphics in weather forecasts in the late-1970s, originally called "Weathervision" (no relation to the weather ...
Office Of Oceanic And Atmospheric Research - What NOAA Research Does - Atmospheric Research
... improvements in forecast and warning services provided by the National Weather Service are a direct result of NOAA research ... observations gathered by satellites and Doppler weather radars (NEXRAD), and sophisticated weather warning and information processing and communications systems, have collectively led to ...
Space Weather
... Weather is not limited to planetary bodies ... ejections, form a system that has features analogous to conventional weather systems (such as pressure and wind) and is generally known as space weather ...

Famous quotes containing the word weather:

    This is the weather the cuckoo likes,
    And so do I;
    When showers betumble the chestnut spikes,
    And nestlings fly:
    Thomas Hardy (1840–1928)

    Whenever the weather licks the pilot instead of him lickin’ the weather, he’s finished. The first time makes the second time easier. And the first thing he knows, he’s in trouble when the weather is perfect.
    Frank W. Wead (1895?–1947)