December offers the longest nights of the year in the northern hemisphere. The winter solstice falls around 21 December, and at high latitudes - northern Norway, Iceland, Svalbard, northern Finland - the polar night has been in effect for weeks. All three tiers of northern location rate as good. Arctic sites at Kp 1-2, mid-latitude sites at Kp 3-4, and even the lower-latitude fringe locations at Kp 5 and above all have the maximum available darkness for their latitude. Tromsø and Alta are in polar night through the month; locations at 60°N such as Bergen and Helsinki have 5 to 6 hours of midday twilight but 12 to 14 hours of genuine night.
The main challenge in December is weather. Mid-winter conditions across northern Europe and North America bring cold, cloudy systems. Cloud cover is the decisive variable on any given night - a clear December night at Abisko or Yellowknife can be exceptional, while a cloudy one at Tromsø produces nothing. Cold, high-pressure anticyclone systems are the friend of aurora watchers in December: they bring stable, clear skies and often extend for several nights. Watching weather patterns a few days ahead and positioning to intercept a clear window gives the best results.
Southern hemisphere aurora is not available in December. Midsummer south of the equator means the high-latitude sites in Patagonia, New Zealand's far south, and Tasmania have no astronomical darkness. The southern aurora australis season will not restart until February.
Planning your trip in December
Deep winter at all northern aurora destinations. Tromsø averages -4°C to 0°C with frequent cloud and occasional snow. Finnish Lapland drops to -15°C to -25°C on clear nights. Swedish Lapland around Abisko is similar. Canadian interior (Whitehorse, Yellowknife) can reach -30°C or below. Iceland is milder but cloudier, around -2°C to 3°C. Christmas and New Year demand affects all destinations.
Maximum darkness. Tromsø is in full polar night - no sun above the horizon at all. Svalbard at 78°N has been in polar night since late October. Iceland at 65°N has around 18 to 19 hours of darkness. Finland at 68°N has near-continuous darkness. Scotland at 57°N has around 16 to 17 hours of darkness. The solstice on 21 December marks the longest night.
December is peak season, particularly around Christmas and New Year. Tromsø, Reykjavík, and Rovaniemi are at their most expensive and heavily booked. Book three to six months ahead for the Christmas-New Year period. The first two weeks of December are notably cheaper than the holiday period. Yellowknife and Churchill in Canada are moderately priced but require planning for the remote logistics.
