The weather is hot.

Meaning: This sentence describes that the state of the atmosphere at a particular time and place has a high temperature.

Choice of Words: The is used to specify that we are talking about a particular weather. Weather is a noun that refers to the state of the atmosphere at a particular time and place. Is is a verb that indicates the state of being. Hot is an adjective that describes something with a high temperature.

Alternative Expressions

The sun is shining.

Meaning: This means that the sun is emitting light and it's visible in the sky. It's like saying, The sun is out and it's making it bright outside.

Choice of Words: The is a definite article that refers to a specific thing. Sun is a celestial body that emits light and heat. Is is a present tense verb that indicates the state of being. Shining is a present participle verb that describes the emission of light.

It's raining.

Meaning: This means that water is falling from the clouds and it's wet outside. It's like saying, The rain is coming down from the sky and it's making the ground wet.

Choice of Words: It is a pronoun that refers to something that has been mentioned before or is understood from the context. Is is a present tense verb that indicates the state of being. Raining is a present participle verb that describes the falling of water from the clouds.

Related Expressions