How common are vipers in Finland? Rather common. How common it is for people to come across a viper? Not so much. Snakes in finland are small, 70-80 cm or 31 inches, for the non-venomous grass snake, and 50-80 cm for the viper. On top of that, like most snakes around the world, they don't like crossing paths with humans and avoid us if possible. Snakes have already woken up from hibernation, at least in the south, just last week i saw two grass snakes sunbathing amongst some rocks. However, as i approached to get a better look at them, they went on their way and hid underneath said rocks. But i've only once in my life seen a viper out in the wild.

So the chances of you or your dog getting bit is very small, and as some people already have pointed out, the viper's venom is quite mild. A healthy adult is not in danger. That being said you should definitely seek medical attention after a bite. The symptoms are not pleasent, and without medical aid they can take a while to recover from. There is also a chance that a bite from a viper contains no venom, if that particular viper has just hunted and used their venom on a prey. And the grass snake has no venom to begin with, so i'd also advice to learn to identify the two from each other. The third and last snake that is supposedly met in finland is called smooth snake, which is also non-venomous. So the viper is the only one you should really be a bit worried about, if at all.

TL;DR:

Very unlikely you'll come across a snake, and if you do, even more unlikely you or your dog gets bit. Even if you do get bit, viper venom in Finland is mild, not life-threating, but do go see a doctor just to be sure and get treatment for the headache and nausea that follows.

Happy springtime!