Our ability to tan is reflective of our ability to utilize the suns energy!
Personal anecdote - I have Irish and German heritage (blonde hair, blue eyes, fair skin) but this summer I have had a crazy amount of compliments from friends, coworkers, and strangers about how tan I am.
The first big thing I did to increase my ability to tan and reduce sunburn is cut out PUFAs both internally and externally a few years ago - this got be about 50% of the way there!
The next thing that really moved the marker is getting outside and getting sunrise light on my eyes and skin every morning FIRST THING - before going on my phone or opening the fridge. I spend at least 5 minutes out there but try and max my time. Then about an hour after sunrise, during the UVA rise I go on a walk for at least 20 minutes.
Finally, just like you said, I get outside during the peak UV hours starting in the spring! Since implementing this consistently last winter, I have seen the greatest improvements in my ability to tan and decrease in sunburns.