The document outlines 3 principles that the Norwegian Meteorological Institute's open data policy is based on: 1) The decision for an open data policy is made by management, while how the data is made available considers users; 2) What meets the Institute's needs also meets re-users' needs; and 3) Dialogue with re-user communities incorporates their feedback. It also notes some lessons learned: data will be used in new ways, re-users help with expertise, and re-users gain competence to understand provided data, while legal issues in this field provide no simple solutions.