I'm with Orion and PA12DRVR on this one reference to northern lights viewing in Alaska that they pointed out in their posts that I will elaborate on....
It is a crapshoot when skies will be clear anywhere in the far north to plan on arriving, however in all my years living here in the Fairbanks area - the best two months of northern lights viewing by far are : March and September
1. - March - When people in other regions personally ask me when is the best time or best chance to view the northern lights, March is the only time I recommend if they are going to invest a travel trip from abroad...
For one, March seems to always have the most clear sky days and nights out of any month of the year....and generally I would notice seeing the lights most every night in March when it is clear in this area.
For two, one would not be generally be exposed to -30 F something below temperatures at all as -20 F to -25 F below is still common lows in March....Fairbanks low temps in general during March on a clear night will average between +10 F to -20 F depending on the current coldfront or warmfront.
March is also the month of the year that the sun exposure gains the most in the Fairbanks area, almost 7 minutes each day times 31 days - which amounts to 11 to 15 hours of twilight per day which in turn still having a potential 14 to 9 hours of nightfall to still view the northern lights.....which would give a visitor the best of both nice sightseeing days and great potential clear viewing nights.
As noted, the Ice Sculpture event happens during March as a lot more events in Fairbanks take place in March rather then in December....Hopefully the Ice Sculpture event will be back up and running again.
I have only witnessed -30 F below lows for a week straight in the month of March only once in 1992, and never seen it -40 F below in March ever until 2007 when the low temps were -40 F to -44 F below for the first two and a half weeks - unbelievable !
As mentioned, the equinox months of earth also happen to be March and September and most active for season change cycle for majority of the planet, which I would guess makes sense due to increased solar activity.
2. - September - On clear nights, late August and September seems to be hit and miss with aurora activity although can be dazzling at times....quite a few times when I go stealth and leave home driving at night on my way to Tok in my camper getting a head start to Canada this time of year, I get a great northern lights show for 200 miles straight non stop and turn off my headlights when there is no oncoming traffic and really enjoy them while driving.
However there are not as many clear nights in August and September as it does tend to rain, or snow at times during September which means cloud cover and no viewing.
For the OP and the large group planning on a December trip to Fairbanks, as others have chimed in reasons why it would not be the best timeframe to do so, I will also elaborate in my perspective :
Fairbanks weather history has shown December to be moderately in the top three snowiest months during the winter the majority of time, which means not a lot of potential northern light viewing compared to March....
If there is no warm trend or snowing a lot in December, you can bet it is going to be a potential 62 day January which is going to be downright bitter cold with daytime highs in the -40's F below or perhaps colder, and it's going to prolong to a multi week coldspell that a visitor will not like - and if it happens to reach record cold temperatures of -60 F for a visitor with no end in sight when a coldspell like that would appear, everything shuts down - transportation, airports, etc.....
Although the conditions will be right for northern lights viewing, there are at times no aurora activity during these prolong coldspells in my experience this time of year....
Also to note that if one is in Fairbanks at -35 F below (particularly during -45 F below or colder), head to the foothills nearby and get out of the ice fog to view the northern lights at it's best when they are ampin'.
With less than 4 hours of sun over the horizon per day in December, daytime highs will not significantly make a difference in the Fairbanks area until late February under clear skies, as during November thru February us Interior Alaskans have to rely on cloud cover or warm trend weather fronts to get any above 0 F temperatures.
Whenever Interior Alaska starts a prolong multi week nasty coldspell, it will generally start in November, December, or January.
As noted, airfare is higher priced in December because of the holidays.
I personally would go against the advice of renting a car if one is planning to drive the 60 miles east on Chena Hot Springs Road to the resort, as it is not the nicest road to drive on during the winter, especially if one is not a seasoned winter driver let alone a visitor unfamiliar with this roadway (plus the fact if the rental car issued is not equipped with winter tires).
There are many careless drivers in a hurry thru mile 20, then traffic gets lighter from there however there are a share of DUI drivers and other accidents too because of driving too fast in prudent conditions because of the frost heaves and blind curves due to slick conditions in the higher elevations where there are warmer temperatures in the various foothills....
Take the shuttle to Chena Hot Springs Resort instead.
As for the OP, I would reconsider visiting the Fairbanks area to see the northern lights during March instead, or if December is the only option, consider Southcentral Alaska where the temperatures are much milder in the winter south of the Alaska Range, however it is a pretty good chance of potential coastal cloud cover to run into, as a short commute inland with a clear weather forecast would in my opinion have the same chance of seeing the northern lights there as Fairbanks in the month of December, plus you get a couple more daylight hours per day of sightseeing there in December without the bitter cold weather.
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