Weather Boosted but Terrible IV

Well, if there's no other possible values it could have, then you did the experiment and proved the minimum 5 hypothesis incorrect. I've seen both 4 and 5 as the proposed minimum, and I personally never caught a weather buffed 4, but lots of 5's.

Using Pokeassistant I get several different IVs and Levels for your Pokemon.

Wild caught weather boost has 4 as minimum IV

Putting in the same info, I'm getting the possibility of 6/5/5 as well 6/6/4. Did the Appraisal tell you that the Attack/Stamina were equal?

I had done some analysis of my own when the weather boost was first introduced across two profiles and can say from my experience that no stat IV is less than 4 when boosted.

4