The Latin roots suggest that something which is evident should always be able to be seen clearly ("obvious to the eye or mind"). In the example sentence given, the word "clearly" is redundant, but in a comparison one conclusion could be more clearly evident than another.

That being said, the phrase "clearly evident" does have some usage.
https://books.google.com/ngrams/graph?content=clearly+evident&year_start=1800&year_end=2000&corpus=15&smoothing=3

Other sources:
http://www.merriam-webster.com/dictionary/evident
https://www.google.com/search?q=define%3Aevident

The Latin roots suggest that something which is evident should always be able to be seen clearly ("obvious to the eye or mind"). In the example sentence given, the word "clearly" is redundant, but in a comparison one conclusion could be more clearly evident than another.

That being said, the phrase "clearly evident" does have some usage.
See Ngram.

Other sources:
http://www.merriam-webster.com/dictionary/evident
https://www.google.com/search?q=define%3Aevident