North Atlantic Current system, moderates Svalbard's temperatures, particularly during winter. Winter temperatures in Svalbard are up to higher than those at similar latitudes in Russia and Canada. The warm Atlantic water keeps the surrounding waters open and navigable most of the year. The interior fjord areas and valleys, sheltered by the mountains, have larger temperature differences than the coast, giving about warmer summer temperatures and colder winter temperatures. On the south of Spitsbergen, the temperature is slightly higher than further north and west. During winter, the temperature difference between south and north is typically , and about in summer. Bear Island has average temperatures even higher than the rest of the archipelago. Svalbard is where cold polar air from the north and mild, wet sea air from the south meet, creating low pressure, changeable weather and strong winds, particularly in winter; in January, a strong breeze is registered 17% of the time at Isfjord Radio, but only 1% of the time in July. In summer, fog is common, particularly off the coast, with visibility under registered 20% of the time in July and 1% of the time in January, at Hopen and Bjørnøya. Precipitation is frequent, but falls in small quantities, typically less than per year in western Spitsbergen. More rain falls on the uninhabited east side, where there can be more than . On average, Svalbard has lower humidity than other places in the Arctic Circle. The only places in the Arctic with a lower average are in mainland Norway, Sweden and Finland). 2016 was the warmest year on record at Svalbard Airport, with a remarkable mean temperature of , above the 1961–90 average, and more comparable to a location at the arctic circle. The coldest temperature of the year was as high as , warmer than the mean minimum in a normal January, February or March. In the same year, the number of days when there was rainfall equalled the number of days when there was snowfall, a significant deviation from the usual pattern whereby there would be at least twice as many snow days. Global warming has resulted in noticeable climatic changes on Svalbard. Between 1970 and 2020, the average temperature on Svalbard rose by 4 degrees Celsius, and in the winter months by 7 degrees. On 25 July 2020, a new record temperature of was measured for the Svalbard archipelago, which is also the highest temperature