Depends on the Milky Way doesn't it. You want it to be from horizon to horizon or just when the brightest parts start to show up...

I'd say in order to "recognize" the MW from the sky you need:

Winter Milky Way (Auriga and below) requires ZLM 6+
Summer Milky Way (Cygnus/Cassiopeia-region) requires ZLM 5.5+

Sagittarius-Scorpius region is pretty much 5.0 or something. It is not visible from Finland so I cannot say much about it - at least from the 5.0 ZLM magnitude (I've never observed from such a horrible place)...

Also the Canis Major and below area is pretty bright Milky Way-wise but it too is invisible from Finland.

/Jake