Is natural sunlight enough for my sulcata?

[Pirapat]

I'm from Thailand and we don't have winter here, so my tortoise always get natural sunlight whenever he wants it all year round(he has an outdoor enclosure). Is that enough? Everyone on the internet is saying that natural sunlight isn't enough, but I presume that they're not talking about tropical areas.

 

[Sheldon the russian tortoise]

If he is in an outdoor enclosure the natural light is plenty

 

[wellington]

It's the best kind of heat and UVB he could have as long as he can stay warm enough.