If you're talking about pigmentation, from my experience, this map of Italy is pretty accurate.
All of my ancestry comes from the area from LaSpezia in Liguria north, encompassing the orange and yellow areas.
This is a medieval fair in one of our villages. The two boys on either end are of local ancestry, but the middle boy is not. The boy on the left as you look at the picture looks just like my cousin Anthony as a child although my cousin's hair was really carroty in shade.
This is a famous partisan from my area:
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This is an Italian skier from a town in my father's area.
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A partisan from an area near my father's, and a famous post war Italian politician. She reminds me of my father's mother.
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This is a folk group from the quattro-province from an area northwest of my father's. They sing all the same songs. My brother, who takes after my father's family more than I do looks a lot like the lead singer, except he has reddish brown coloring like the singer with a beard.
https://www.youtube.com/watch?v=CkBYn-AYULU
So, I wouldn't say it's rare at all in Italy as a whole.
Not everybody in those areas is fair, of course; I'm just saying it exists in a decent percentage. A lot of our songs are about a biondo or bionda.
One can also find them occasionally in southern areas. My husband's maternal grandmother was from around Benevento in Campania, and she was blonde and blue eyed, as is his sister, and his paternal grandfather from Calabria had light brown hair and green eyes, and was 6'3. He got his "Mediterranean" coloring from his other two grandparents.
Ed. the map figures are based on military conscripts so they're really only for men. Women are fairer so the over all percentages are probably a bit higher.