Winter (November–March): Polar night and cold (down to -20°C), but this is Northern Lights season — clear skies and good aurora activity from late October through February. Dog sledding and snowmobile safaris are at their best, and the blue twilight around midday has a quality of light found nowhere else. February and March bring the sun back and are arguably the finest months, with snow still deep and daylight returning.
Spring (April–May): The midnight sun begins in late April and doesn't set again until late August. Snow is still on the ground in April; May is transitional. Good for skiing and snowmobile trips before the snow melts.
Summer (June–August): Midnight sun, boat expeditions to glacier fronts, hiking, and birdwatching. The landscape turns surprisingly green. Most wildlife boat tours run in summer. Warmer (5–10°C) but often foggy.
Autumn (September–October): Transition period with dramatic light and thinning crowds. First snow arrives in October. Good compromise of accessibility and atmosphere.
Pack for cold regardless of season. Wind chill is the main hazard; layering is essential. Polar bear awareness is year-round outside town.