Nouns ending in -ence are usually feminine.
The suffix forms abstract nouns, often from verbs.
Is expérience masculine or feminine?
l'expérience
The rule behind it
97.6% of -ence nouns are feminine
In context
C'était une très bonne expérience pour lui.
It was a very good experience for him.
Il a la connaissance ainsi que l'expérience.
He has knowledge and experience as well.
Il consacra toute son énergie à l'expérience.
All his energies were devoted to the experiment.