In the Nordic countries, besides Norway, it is required to have turned 18 years before the day of the election. Whilst in Norway it is sufficient to turn 18 years old by the end of the year of the election.
On Iceland, Nordic-citizens can vote if they have registered as living on Island for three year or more before the Election Day. While In Denmark, Nordic citizen can vote from the day they register as living in Denmark.
In Sweden and Finland, Nordic citizen have to be register 30 day before the election (Sweden) or 51 days before the election (Finland).