Hey guys, currently own a 4 month old veiled. I want to put him in my backyard but there's no direct sunlight. Most of it is blocked by the trees in my backyard, will that be an issue as far as uvb goes?
There will be SOME UVB. Depends on how shady it is. You wouldn't really know how much is in the shade without a 6.2 Solar meter that measures UVB.
If there is any time during the day that he would get a bit of sun then he is fine. I think he will be OK out there regardless unless there are multiple levels of trees/leaves/branches blocking off the light.
This is where a UVB meter comes in really handy, as Seiryu previously stated. I have found that (in Cincinnati anyway) UVB in the shade is similar to UVB from a Reptisun 5.0 at about 8" (partially blocked by the screen cage). I am not sure if that alone would be sufficient or how you would adjust d3 supplementation.
I do wonder however if the lack of a direct basking opportunity for your cham would have any negative consequences on his metabolism and digestion.