2012 Year in Review - Fairbanks

Persistently colder than normal temperatures along with near normal precipitation and snowfall for Fairbanks for 2012


The mean temperature for Fairbanks in 2012 was 24.1F, 3.5F below the long-term average of 27.6F. This makes 2012 the coldest year of the new century, and continues the cooling trend observed over the last decade. More information on the recent cooling trend in Alaska can be read in this paper from the ACRC. Looking further back in time, 2012 was the second coldest year in the last forty for Fairbanks. Only 1999, with a mean of 23.4F, was colder. The mean temperature for 2012 was more reminiscent of what Fairbank's routinely experienced earlier in the 20th century. 2012 was also notably colder than 2011, which had a mean temperature of 28.0F.

The highest temperature of 86F was observed on the 23rd of June, close to the summer equinox with over 21½ hours of sunlight. June 23rd was also the day with the highest mean daily temperature of 71.0F. There were only five days with temperatures at or above 80F, less than half the long-term normal of twelve days. The lowest temperature of the year was -51F, occurring on the 29th of January, while the 28th of January was the coldest day in terms of the daily mean temperature at -46.0F. There were a total of 26 days with lows at or below -40F, more than twice the long term normal of eleven days. The only temperature record for 2012 was a new daily high set on April 16th with 61F, topping the 1993 record of 59F.

 

Month

Temperature

Observed
(F)

Normal
(F)

Delta
(F)

January

-26.9

-7.9

-19.0

February

5.9

-1.3

7.2

March

4.5

11.4

-6.9

April

36.9

32.5

4.4

May

47.9

49.4

-1.5

June

61.6

60.4

1.2

July

60.8

62.5

-1.7

August

56.3

56.1

0.2

September

45.5

44.9

0.6

October

22.5

24.2

-1.7

November

-8.8

2.6

-11.4

December

-17.3

-4.1

-13.2

 

Looking at the temperature data by month, it can clearly be seen that the colder than normals temperatures were not evenly distributed throughout the year. Below average temperatures were more prominent during the winter months, while summer experienced more normal temperatures. January had the greatest deviation of -19.0F. The actual mean temperature for the month was a frigid -26.9F, the coldest January in more than 40 years. Large negative deviations were also observed in December (-13.2F), November (-11.4F) and March (-6.9F), while February was above normal with a positive deviation of 7.2F. The rest of the year had no other remarkable deviations from the long-term mean.

The temperatures of Alaska are strongly affected by the Pacific Decadal Oscillation, which is an index derived from the surface temperature of the waters of the North Pacific Ocean. Warm temperatures in Alaska are related to positive PDO values, while negative values indicate below normal temperatures. Before 1975 this index was predominantly negative, and the temperatures up to that time tended to be cool. After 1976 the PDO values switched to predominantly positive and warmer temperatures were observed. With the start of the new century, the PDO values trended to the negative again, and a cooling started. With colder surface waters, the semi-permanent Aleutian Low weakens, and less warm air is advected into Alaska. While this is of minor importance in summer, as days are long, in winter the solar elevations are low, the days are short, and this transport of warmer air from the south greatly influences the Alaskan temperatures. For more details of the annual course of temperature for Fairbanks, see the figure below.

For 2012 the Precipitation total was 10.62", very close to the expected value of 10.81". Highest daily total was 0.82" and occurred on August 26th. Five months of the year had precipitation deficits, while six had excesses. February hit its normal value of 0.42". The annual course over the year also followed fairly closely the long-term mean value, as can be seen from the third figure. 2012 was wetter than 2011, which saw a total of only 9.52". As might be expected from the near normal precipitation, the snowfall of the year was close to normal with a total of 61.7", only 3.3" below the normal of 65.0". Interestingly, this is the same snowfall total as for 2011.

Despite the near normal annual precipitation and snowfall, there were a number of records set in 2012. March 6th saw a snowfall of 2.6", tying the previous record set way back in 1932. The precipitation equivalent was 0.17", and this was a new daily record, breaking the old record of 0.15" set in 1967. The storm continued on into the next day, and 6.9" more snow fell, smashing the 1943 record of 3.5". The precipitation equivalent came to 0.28", a new record too, topping the old 1985 record of 0.24". Then on May 25th a total of 0.52" of rain tumbled down, just outdoing the 1973 record of 0.50". Two events occurred at the beginning of October. First, 0.21" of rain fell on the 6th, tying the 1989 record. This was followed on the 7th with 0.55", eclipsing the 1974 record of 0.28". A final snowstorm in December dropped 9.5" of snow on the 12th, which broke the 1972 record of 5.7". On the same day, the precipitation equivalent was 0.72", shattering the 1972 record of 0.17".

The last day of seasonal snow cover was April 22nd, and the last frost of the winter came on May 14th. Green up day occurred on the 10th of May, which is about normal. Growing degree-days totaled 1003 and the growing season was 117 days long, about average. The first frost hit on September 10th, and the snowpack was re-established on October 15th. As might be expected, heating degree-days was 1297 above the normal of 13666. Correspondingly, cooling degree-days totaled just 34, 27 less than expected. Mean annual wind speed was 3.3 mph, with lower values in winter, when the semi-permanent inversion decouples the surface conditions from the upper circulation.

Less than 300,000 acres burned due to forest fires, a relatively low value, as the mean over the last 50 years is about 1 million acres. This is understandable, as there were fewer hot days in 2012. Hotter days cause both a higher number of lightning strikes (starting new fires) and allow existing fires to expand. The most vexing fire for the Fairbanks area was the Dry Creek fire. It started on June 23rd about eighteen miles south of North Pole, and continued to occasionally send smoke into the unban area until after the middle of September.



2012 Statistics
Mean Annual Temperature 24.1°F
Departure from Normal -3.5°F
Highest Temperature 86°F (23 Jun)
Mean Highest Temperature 71.0°F (23 Jun)
Highs Above 80°F 5 days (Average: 12)
Lowest Temperature -51°F (29 Jan)
Mean Lowest Temperature -46.0°F (28 Jan)
Lows Below -40°F 26 days (Average: 11)
Total Precipitation 10.62 inches
Departure from Normal -0.19 inches
Maximum 24hr Precipitation 0.82 inches (26 Aug)
Total Snowfall 61.7 inches
Departure from Normal -3.3 inches
Maximum 24hr Snowfall 9.5 inches (12 Dec)
New Record Highs / Lows 1 / 0
New Record Precipitation / Snowfall 6 / 3
Heating Degree Days 14963
Departure from Normal 1297
Cooling Degree Days 34
Departure from Normal -27
Growing Degree Days 1003



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Questions or comments? Please contact the Alaska Climate Research Center.
Preliminary climatological data are used for this summary. Please report any errors found to the Climate Center

Posted: 16 February, 2013