Weather is a day to day phenomenon that describes the condition of the atmosphere of a particular place. It might be sunny, hot, windy or cloudy, raining or snowing. Weather also speaks about sunshine, temperature, amount of cloud cover, wind and fog condition, air pressure, humidity, precipitation and other elements. It refers to short durations like a day, a week, a month, or litter longer than that. Weather is dynamic and keeps on changing from time to time in a day or a period of a year.
Composition of Earth's Atmosphere
Carbon dioxide0.03%
Trace amounts of other gases and water vapour0.04%
As we mentioned earlier, weather changes from time to time. It may be a sunny morning with a clear sky in a particular place, but on the same day, there might be a heavy downpour in the evening. Similarly, a place may have cool winter and hot summer.

We often hear people using weather and climate interchangeably. But, it is incorrect because they both are different. Weather is for a short duration, and it varies for a brief time. But the climate of a place or a region is for a very long time.
Usage of weather
Correct: There is a sudden change in weather today morning.
Wrong: There is a sudden change in the climate today morning.