climactic and climatic - the difference
 
Climactic pertains to the highest point. Climatic pertains to the weather.
 

Climactic

The adjective climactic derives from the noun climax. It pertains to a peak, a decisive moment or the point of greatest tension.

Examples:

In the climactic scene of the movie, the aliens emerge from the capsule and start zapping the onlookers.

Who would have thought that the season would have ended in such a climactic way?

Climatic

The adjective climatic derives from the noun climate. It pertains to the weather.

Examples:

Climate change is defined as the long-term significant change in the expected patterns of weather.

His assessment of the eco-climatic system over Africa is based solely on satellite data.

See also:

What are adjectives?
What are nouns?
List of easily confused words