Östersund has a temperate continental climate and is located in the far north of the north temperate climate zone. The cold Arcticwinds that occasionally find their way to the city are called nordvästan (the north-westerner) or kallvästan (the cold-westerner) locally.
However the winter climate is much warmer than most locations at similar latitudes. This is due to the gulf stream and the many passages in the mountain range, bringing warmer Atlantic winds to the city during winters. This somewhat maritime character also makes the summers in the city rather cool, in comparison to other towns in inland Scandinavia, which all have a more continental climate with cold winters and warm summers.
Though Östersund is in fact affected by the gulf stream it lacks the high frequency of rain following the currents. This is due to the Scandinavian Mountain Range acting as a natural barrier, receiving most of the precipitation, giving Östersund and the surrounding area a rain deficit.
Östersund has a high exposition of sunlight and was the most sunny city in Sweden in the summer of 2007 (July 1 - August 9) with 654 hours of sun