Earth

[beanaseireann]

..... is the warmest place on Earth.
or
...... is the warmest place on earth.

[DadDadDad]

I'd go with Earth as you talking about a specific planet and that is its name. Just as you would talk about the hottest place on Mars.

[beanaseireann]

Thank you

[beanaseireann]

I still don't understand why the seasons are common nouns