Narvik has two very distinct travel seasons.
Summer (June–August) brings the midnight sun: from about 27 May to 17 July the sun never sets, and the light stays bright through the night. Temperatures sit around 15–20°C at sea level, sometimes briefly higher. This is the time for hiking the Rallarvegen along the ore railway, climbing to the cable-car platform at midnight, and fishing the fjords by small boat.
Winter (late November–February) brings the polar night — from 7 December to 5 January the sun does not rise — and with it three of Narvik's main draws: alpine skiing at Narvikfjellet, killer whale safaris in the fjords, and excellent chances of seeing the northern lights away from the lights of town. February has lengthening days and is often the best month for snow.
Shoulder seasons. April and May can be very pretty as snow melts in the lowlands but lingers high up, and September brings short autumn colour on the birches before the snow returns.