Weather describes the short-term conditions of the atmosphere — temperature, humidity, precipitation, wind, and cloud cover. Climate is the long-term pattern of weather in a region.

The water cycle is the continuous movement of water through Earth's systems. It has four main stages: evaporation (water becomes vapor), condensation (vapor forms clouds), precipitation (water falls as rain or snow), and collection (water gathers in bodies of water or soaks into ground). The Sun's energy drives the water cycle.

Different types of clouds indicate different weather. Cumulus clouds are fluffy and often mean fair weather. Stratus clouds are flat layers that may bring steady rain. Cumulonimbus clouds are tall and bring thunderstorms.

Weather is measured using instruments: thermometers (temperature), barometers (air pressure), anemometers (wind speed), and rain gauges (precipitation).