The horizontal visibility is quantified using observations made by meteorologists in the surroundings of the Hornsund Station with a marine scale that range from 1 to 9. The visual observations are performed using known distances to the surrounding mountains and other objects. Values 1 and 2 correspond to very bad visibility, 0-50 m and 50-200 m, respectively. Bad visibility (200 m - 1 km) is represented by value 3. Weak horizontal visibility represents conditions with 1-2 km and 2-4 km that are quantified as 4 and 5 in the applied scale. Moderate horizontal visibility, described as 6 in the scale, represent conditions when an object or light can be clearly discerned from 4-10 km. Good horizontal visibility (7 in the scale) is 10-20 km, very good (8) 20-50 km and extremely good (9) is for horizontal visibility larger than 50 km.