They are actually quite common here. There are 3 different kinds of snakes in Finland, of which only one is mildly poisonous (the very one I captured above)
The other two are much rarer, I have only ever seen each of the non-poisonous snakes once in the wild.

They all go to deepsleep during the winter on burrows below ground, and only wake up when the temperature rises up way over freezing. On the spring they start to wander around to get to warm places, as tehy really are the true children of the sun, they love warmth and can only move quickly in warm conditions.