Noun

Singular weather

Plural countable and uncountable; plural weathers

weather (countable and uncountable; plural weathers)

1. The short term state of the atmosphere at a specific time and place, including the temperature, humidity, cloud cover, precipitation, wind, etc.
2. unpleasant or destructive atmospheric conditions, and its effects.

   Wooden garden furniture must be well oiled as it is continuously exposed to weather.

3. (nautical) The windward side of a ship.
4. (countable, figuratively) A situation.

Synonyms

• (windward side): weatherboard

Derived terms

• weather balloon
• weatherboard
• weathercast
• weathercock
• weather deck
• weather eye
• weather forecast

• weather front
• weather gauge
• weatherise / weatherize
• weatherly
• weatherman
• weatherperson
• weatherproof

• weather report
• weather shore
• weather speak
• weatherstrip
• weather summary
• weather vane

Weather is a set of all the phenomena occurring in a given atmosphere at a given time. Weather phenomena lie in the troposphere. Weather refers, generally, 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 occurs due to density (temperature and moisture) differences between one place and another. These 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 to hundreds of 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

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.