We had Christmas yesterday at my brother's house. It was so warm we opened windows and ended up with flies and mosquitos inside! In contrast my daughter was born in 1983...coldest December on record...
The coldest period occurred during a ten day stretch beginning on the 16th and ending on Christmas day. In Sioux Falls the average temperature during this period was 14.2 degrees below zero which was 32.3 degrees below normal! The average high during this ten day period was 6.2 degrees below zero and the average low, 22.1 degrees below zero. Contrast this with what the average high should be during this period, around 26 degrees, and the average low during this period, around 7 degrees, and you begin to understand the magnitude of this unusually harsh cold spell.
During this same ten day period the average temperature in Sioux City was 9.5 degrees below zero which was 31.3 degrees below normal. The average high was 3.3 degrees below zero and the average low 15.7 degrees below zero. Normally during this period the high temperature should be around 29 degrees and the low around 11 degrees.
In Huron, the average temperature between December 16th through Christmas day was 12 degrees below zero which was 29.5 degrees below normal. The average high during this ten day period was 5.3 degrees below zero and the average low 18.8 degrees below zero. Normal high and low during this period would be around 27 and 6 degrees respectively.
It was also during this ten day Arctic invasion that both Sioux Falls and Sioux City broke their records for most consecutive days with temperatures at or below zero, 9 1/2 days in Sioux Falls and 8 1/2 days in Sioux City.
In Sioux Falls, the mercury dropped to zero degrees shortly before midnight December 15th and it wasn't until shortly after noon on Christmas day before the mercury would climb above zero degrees.
In Sioux City, the temperature fell to zero degrees during the late evening on December 16th and it wasn't until shortly before noon on Christmas day when the mercury climbed above zero.
In Huron, the temperature fell below zero degrees shortly before midnight on the 15th and remained below zero until around 10 am Christmas day.
Because of the extreme cold during December 1983 no snow melt occurred and additional snows that fell were of the dry fluffy variety that blows and drifts a lot. On the 20th, from 3 to 4 inches of dry fluffy snow fell across the area which served as ammunition for the biggest Arctic blast of the month which occurred late on the 23rd and continued into the 24th. High winds and loose snow produced zero and near zero visibilities through much of the day in Sioux Falls on the 24th. Shortly after midnight the temperature in Sioux Falls was 22 degrees below zero which when combined with a northwest wind averaging 30 mph combined to produce an apparent wind chill temperature of 82 degrees below zero. The high temperature that day was only 13 degrees below zero and the barometric pressure rose to a near record high 31.06 inches. In Sioux City, howling northwest winds produced zero or near zero visibilities through much of the morning with an apparent wind chill temperature of 80 degrees below zero around 3 am when the air temperature was 17 degrees below zero and the average wind speed was 41 mph! The high temperature that day in Sioux City was 11 degrees below zero. In Huron, visibilities were zero or near zero through the early morning with an apparent wind chill temperature of 77 below zero shortly after midnight on the 24th with a temperature of 20 below zero and a northwest wind averaging 29 mph. The high temperature on the 24th in Huron was 10 degrees below zero.
