Bogotá is at 2640 m, so there is more unfiltered radiation. Like 20-25% more UV. And it's cooler so you don't notice it as much as you should. You can get sunburns even with clouds at that altitude.

Bogotá is 4 degrees north of the equator. Its climate is a bit temperate due to being in a high altitude plateau. But you better wear sunscreen anyway under tropical sun.

As a Colombian now living in the north, every time I return to Bogotá, the UV index is between 9 and 11, and I get sunburned. My skin has become accustomed to the 1-2 levels typical of Northern Europe.

It's at an altitude of 8500+ ft - UV is much stronger and the sunburns can be bad if you're not prepared.

Um actually it's more "blistering" than in So Calif (where I also lived most of my life) due to the altitude.

Why are you so sure? What information do you have that leads you to be that sure?