Do raid bosses have better IVs on average?
Currently if you successfully catch a raid boss, the level of the Pokemon is level 20. Like hatching a Pokémon from an egg.
The IVs distribution differentiate between 10 - 15 Points randomly per stat.
Reference: Data from various catches on Silph Road
Yes, raids produce higher IV pokemons since their stat floors are much higher compared to regular mons. Here are several scenarios:
- Raids = 10/10/10
- Lucky Trade = 12/12/12
- Best friend trade (non-lucky) = 5/5/5
- Weather boost IV (non legendary, non raid) = 5/5/5
- Research Breakthrough = ?/?/?
- For reference: Max IV (100%) = 15/15/15
Weather boost adds 5 levels for all mons. Helpful for Legendaries so you start at level 25 instead of 20 for dust and candy costs. Weather boost does not affect legendary IVs.