With some words, a single letter can completely change the meaning. Take the letter ‘c’ and the words climactic and climatic. There’s not much difference in spelling and the words even sound the same, but there’s a world of difference in meaning.
Climactic comes from the word climax. This has to do with the progression of events, in which the climactic moment is the moment of greatest intensity. It’s that point in a serial killer thriller where it looks like the villain is going to win out against the hero. It’s that point when feelings are at their highest. It can also be used to indicate a pivotal moment in history.
Example: The climactic moment in the early history of man came when our ancestors left the trees and began to walk on the ground.
Climatic on the other hand is all about the climate. If you can use the word weather, then climatic is the word you want.
Example: Severe climatic conditions led to snow storms in July.
Putting It All Together
Now you know the difference, it is easy to tell that the climatic conditions of the Ice Age represented the climactic period of the age of the dinosaurs.