SIOUX FALLS AREA
CLIMATIC SUMMARY
2012

Data compiled by Joe Sheehan
Climatic Focal Point
National Weather Service, Sioux Falls

THE FOLLOWING TABLES GIVE A MONTH BY MONTH BREAKDOWN OF WEATHER IN 2012 AT THE SIOUX FALLS AIRPORT...

TEMPERATURES

AVERAGE                DEPARTURE  EXTREMES    MONTHLY
 MONTH        MAX   MIN     MONTHLY   FROM NORM  HIGH LOW    RECORDS

JANUARY      34.6  13.3       23.9    PLUS  7.4   62  10B
FEBRUARY     36.4  16.7       26.6    PLUS  5.1   50   5B    5TH WETTEST
MARCH        63.5  36.1       49.8    PLUS 16.9   85  15     1ST WARMEST
APRIL        64.2  39.1       51.7    PLUS  5.3   89  20
MAY          73.6  49.8       61.7    PLUS  3.7   91  37
JUNE         84.7  59.5       72.1    PLUS  4.3   96  40     2nd DRIEST
JULY         94.0  68.7       81.3    PLUS  8.3  104  56     2ND WARMEST
                                                             1ST DRIEST
AUGUST       86.1  58.7       72.4    PLUS  1.7  104  40
SEPTEMBER    78.9  46.5       62.7    PLUS  1.4   96  27
OCTOBER      58.1  34.5       46.3    MINUS 1.6   80  20
NOVEMBER     46.9  24.8       35.8    PLUS  3.2   70  12
DECEMBER     31.5  11.6       21.6    PLUS  2.4   61   7B

 2012        62.7  38.3       50.5    PLUS  4.7  104  10B

PRECIPITATION (INCHES) AND WINDS

 
                 DEPARTURE                DEPARTURE     MAX WIND GUST
    MONTH        FROM NORM     SNOWFALL   FROM NORM   DIRECTION/MPH/DATE

JANUARY   0.75   PLUS 0.19         8.2    PLUS 0.5    NW 40 ON  1ST
FEBRUARY  2.43   PLUS 1.83         6.9    NORMAL       W 46 ON 26TH
MARCH     0.77  MINUS 0.99         0.3    MINUS 8.1   SE 47 ON 26TH
APRIL     2.40  MINUS 0.61         0.0    MINUS 4.6    N 53 ON 15TH
MAY       4.60   PLUS 1.20                             N 46 ON 11TH
JUNE      0.74  MINUS 3.18                             S 46 ON 17TH
JULY      0.24  MINUS 2.85                            NW 43 ON 26TH
AUGUST    1.75  MINUS 1.30                             S 45 ON 28TH
SEPTEMBER 1.14  MINUS 1.63                             S 43 ON 10TH
OCTOBER   0.86  MINUS 1.31         1.1   MINUS 0.2    NW 52 ON 18TH
NOVEMBER  0.35  MINUS 1.01           T   MINUS 7.4    NW 48 ON 22TH
DECEMBER  1.31   PLUS 0.62        12.7   PLUS  4.5    NW 45 ON  3RD

 2012    17.34  MINUS 9.04                             N 53 ON 15TH 

Sioux Falls weather for the year 2012 will be remembered for its persistent warmth and a drought that developed during the late spring and worsened during the summer and autumn.

The winter months of December 2011 through February 2012 had above normal precipitation which was welcome following the record dry autumn of 2011. During this three month period precipitation totaled 3.80 inches, more than two inches above normal. Because of the mild conditions much of the precipitation fell as rain. In fact, the biggest daily precipitation total for the year occurred on February 28th when 1.41 inches fell, almost all of it as rain. The 1.41 inches of precipitation broke the daily record of 1.19 inches set in 1951 and was the third wettest February day on record. Also, the biggest 24 hour precipitation total for the year occurred during this storm with a total of 1.46 inches. The rain switched over to snow late in the evening of the 28th which continued into the 29th, with one half inch accumulation (0.05 inches liquid) contributing to the 24 hour total. A total of 2.43 inches of precipitation fell during February 2012 making it the 5th wettest on record. The wettest February on record occurred in 1962 with 4.05 inches.

Precipitation waned during March when a persistent ridge developed during the month, bringing record warmth to much of the Northern Plains region. The last measurable snow of the season fell on March 4th when two tenths of an inch fell, making this one of the earliest last snow events on record. April recorded 2.40 inches of rainfall which was 0.61 inches below normal. No rain fell the first 11 days of the month, which was followed by a two day total of 1.16 inches on the 12th and 13th. The month of May was by far the wettest month of the year with a total of 4.60 inches (1.2 inches above normal). 1.23 inches fell in a 24 hour period on the 19th and 20th for the biggest event of the month. Much more rain fell to the west and north of the city during the month, along with severe weather in the form of large hail on the 5th. Through the end of May, year-to-date precipitation in Sioux Falls was actually in excess by 1.62 inches.

Rainfall diminished greatly across the area beginning in June and the dry conditions continued through the summer and autumn months. 0.74 inches of rain fell during June 2012, the second driest June on record. This was followed by the driest July on record with a total of only 0.24 inches. The previous driest July occurred in 1947 when 0.25 inches fell. A bit more rain fell during August with a total of 1.75 inches, still more than an inch below normal. The rainfall for the months of June through August in Sioux Falls totaled 2.73 inches, which makes the summer of 2012 the driest on record. The previous driest summer occurred in 1894 with 3.55 inches. It was just two years ago the city experienced its wettest summer on record, with 22.64 inches recorded officially at the airport on the north side of town. Rainfall in excess of two feet fell on the south side of the city that summer.

The dry conditions continued into the autumn months of September through November with a three month total of 2.35 inches, which was nearly four inches (3.95 inches) below normal. The first snow of season fell on the 25th of October with 1.1 inches. Above normal precipitation returned in December in the form of rain and snow. On the 15th of the month late night and morning rain totaled 0.61 inches, breaking the daily record of 0.54 inches in 1984. Snowfall for the month totaled 12.7 inches. A total of 6.39 inches of precipitation fell in the city since the beginning of June, a deficit of 10.66 inches. For the year, precipitation in Sioux Falls was 17.34 inches, 9.04 inches below normal, and the ninth driest year on record.

Persistent warmth during the year will make 2012 one of the warmest on record in Sioux Falls. The average temperature for the year was 50.5 degrees which is 4.7 degrees above normal. October was the only month which recorded a monthly average temperature below normal. The warmth started early in the year with a high of 62 degrees on January 5th. This is the earliest occurrence of 60 degrees recorded in the city. The above normal temperatures during the winter months were aided by a lack of snow cover. Unusual warmth developed during the month of March. Seasonably cool temperatures the first four days of the month gave way to an extended period of much above normal temperatures. A ten day stretch beginning on the 10th of the month averaged 58.3 degrees, or 26 degrees above normal. The average high during this period was 74 degrees and the average low 42.6 degrees. Daily record highs were broken on the 10th with 72 degrees, the 13th with 79 degrees, the 15th with 75 degrees , the 16th with 82 degrees, and the 18th with 85 degrees, the warmest day of the month. An additional record maximum was broken on the last day of the month when the mercury climbed to 83 degrees. Night time minimums were also well above average with a low of 60 degrees on the 17th and 63 degrees on the 18th. The prior warmest March night on record was 54 degrees on the 28th in 1981. With an average temperature of 49.8 degrees, the month of March 2012 is the warmest on record, beating out March 1910 at 49.2 degrees. The average temperature of 49.8 degrees is an incredible 16.9 degrees above normal.

The above normal temperatures continued into April and May, with record highs of 89 degrees on April 1st and 84 degrees the following day. With an average temperature of 81.3 degrees, July 2012 was the second hottest July on record. July 1936 is the hottest month ever recorded in Sioux Falls with an average temperature of 84.6 degrees.
The average high of 94 degrees is the third hottest for the month, and nearly five degrees shy of the July 1936 average of 98.9 degrees. There was a 14 day stretch of consecutive days of 90 degrees or more beginning on the 13th of the month. The average temperature during this stretch was 84.2 degrees, around 11 degrees above normal. The average high was 97.1 degrees and the average low 71.3 degrees. The last time the city had a stretch of 90 degree heat this long was in 1974 with a stretch of 15 days beginning on July 12th. The 14 day stretch of 90 degree heat was the fourth longest in history. 1936 had a stretch of 18 consecutive days of 90 degree heat beginning on July 2nd. Temperatures hit 90 degrees or more on 23 days during the month of July 2012 and there were six days of triple digit heat. The 23 days of 90 degree or more heat equals the July totals of 1975 and 1974. July 1936 had a total of 27 days with readings of 90 degrees or more. The six days of triple digit heat for the month equals six days in 1975 and is short of the 1974 total of seven days. During July 1936 there was a total of 16 days with temperatures of 100 degrees or more.

August 2012 was hot at the beginning and end of the month, with cooler than normal conditions in between, especially from the 9th through the 21st. While no record daily highs were broken during July, August had a total of three days, a record high of 102 on the 1st, 100 on the 29th, and 104 on the 30th. For the summer months of June through August, Sioux Falls had 40 days of 90 degrees or more, and 9 days of 100 degrees or more. The 9 days of 100 degrees or more were the most since 1988 when 14 days of triple digit heat occurred. These 9 days also equals the total number of days of triple digit heat observed from 1990 to 2011, a total of 22 years! For the year, a total of 47 days saw temperatures of 90 degrees or more, the most since 1976 with 55 days.

The trend of above normal temperatures continued into September, for the 12th consecutive month beginning in October 2011. The average temperature was 62.7 degrees, 1.4 above normal. The first freeze of the year occurred on September 22nd with a low of 32 degrees, followed by a low of 27 degrees the next morning. A record high was tied on the 11th with 96 degrees and a record low tied on the 23rd at 27 degrees. The string of above normal monthly temperatures ended in October with an average of 46.3 degrees, or 1.6 degrees below normal. November saw a return of mild temperatures with an average of 35.8 degrees, 3.2 degrees above normal. A record high of 70 degrees was established on the 21st, the latest occurrence of that temperature in the calendar year. The first half of December was very mild except for a brief cool down on the 9th and 10th. Below normal temperatures prevailed the second half of the month, with rain and snow becoming somewhat of a regular occurrence. The December average temperature was 2.4 degrees above normal at 21.6 degrees. The first subzero temperature occurred on the morning of December 10th, with a minimum of minus 7 degrees.


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