What is a climatic sentence?

There isn't a universally recognized term called "climatic sentence" in grammar or linguistics. It's possible you might be thinking of something else, or the term is specific to a particular context or field.

Could you please provide more context or information? For example:

* Where did you encounter this term? (e.g., a book, website, class)

* What was the sentence or passage discussing?

* What do you think it means?

With more information, I can help you understand what you're looking for.