Weather
Topic: Atmosphere: Composition, Structure and Elements of Weather · NCERT: Class 7, Ch 2 "Understanding the Weather"; Class 7, Ch 3 "Climates of India"; Class 9, Ch 3 "Atmosphere and Climate"
Meaning
Weather is the state of the atmosphere at a given place and time. It changes from hour to hour and from day to day. Six elements describe it: temperature, pressure, wind (speed and direction), humidity, clouds and precipitation (rain, snow or hail). Often one element stands out. Rain stands out in July, temperature in May and December, and pressure when a cyclone moves in. All weather happens in the troposphere, the lowest layer of the atmosphere.
Example
A typical May afternoon in Delhi shows weather at work. The loo, a hot and dusty summer wind of north India, blows across the plains. On that day wind and temperature matter most.
Don't confuse with
- Climate: the average weather over a large area and a long period, usually 30 years or more. Weather is what happens on a single day.