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.

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

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

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

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.

I did, at any rate, get a sunburn there one November