Joe's Corner

THE DECADE OF THE 1970S

 

AVERAGE YEARLY TEMPERATURE

AVERAGE SUMMER TEMPERATURE

AVERAGE WINTER TEMPERATURE

TOTAL PRECIPITATION FOR THE YEAR

1970

43.8 DEGREES

71.6 DEGREES

14.5 DEGREES

27.38 INCHES

1971

44.9 DEGREES

71.2 DEGREES

14.2 DEGREES

23.64 INCHES

1972

42.7 DEGREES

69.1 DEGREES

12.6 DEGREES

26.43 INCHES

1973

47.5 DEGREES

73.3 DEGREES

18.8 DEGREES

28.19 INCHES

1974

46.3 DEGREES

70.9 DEGREES

18.1 DEGREES

17.03 INCHES

1975

45.3 DEGREES

72.9 DEGREES

19.0 DEGREES

26.10 INCHES

1976

46.9 DEGREES

74.5 DEGREES

21.8 DEGREES

11.42 INCHES

1977

46.7 DEGREES

72.1 DEGREES

15.6 DEGREES

31.62 INCHES

1978

42.7 DEGREES

69.5 DEGREES

8.9 DEGREES

23.17 INCHES

1979

43.2 DEGREES

70.6 DEGREES

8.0 DEGREES

32.25 INCHES

 

 

 

NUMBER OF DAYS 90 DEGREES OR MORE

NUMBER OF DAYS 100 DEGREES OR MORE

NUMBER OF DAYS 0 DEGREES OR LESS

NUMBER OF DAYS -10 DEGREES OR LESS

1970

29

2

39

24

1971

18

4

35

13

1972

20

0

44

26

1973

34

3

19

10

1974

32

8

20

11

1975

36

6

32

8

1976

55

5

34

13

1977

19

3

37

19

1978

17

0

54

33

1979

8

0

43

28

The decade of the 1970s was the coolest of the 20th century with an average temperature of 45.0 degrees. In contrast to the 1990s, the 1970s, on average had warmer than normal summers and much colder winters. The average summer temperature for the decade was 71.6 degrees, the third warmest of the century, while the average winter temperature for the decade was 15.2 degrees, the coldest for the 20th century. The extreme temperatures for the decade also illustrate this with 268 days reaching 90 degrees or higher and 31 days rising to at least 100 degrees. Both marks are the second most for any decade in the 20th century. At the same time, the 357 days of zero degrees or colder is the 2nd most of the century of which 185 days were at or below -10 degrees (most this century). Looking at individual years, 1972 and 1978 had an average annual temperature of 42.7 degrees which tied for the fifth coolest years of the century. And 1979 was not much warmer with an average annual temperature of 43.2 degrees, the 8th coolest year of the century. In fact, the winters of 1977-78 and 1978-79 were especially brutal. The average winter temperature in 1978-79 was 8.0 degrees, the coldest this century, while 1977-78 had an average winter temperature of 8.9 degrees which was the second coldest winter this century. To underscore the frigid weather Sioux Falls experienced those two winters - 1977-78 had 52 days at or below zero (3rd most) with 30 days at or below -10 degrees (3rd most.) The following winter (1978-79) was even more extreme with 54 days at or below zero (tied for first) and 34 days at or below -10 degrees which also tied for the most this century. With such cold winters, several months ranked among the top five coldest - January 1979 was the coldest January of the century with an average temperature of 1.8 degrees. The previous January was not much better. It was the second coldest on record with an average temperature of 1.9 degrees. February 1978 and 1979 were also amongst the coldest of the century with an average temperature of 8.6 degrees (4th coldest) and 7.5 degrees (3rd coldest), respectively. Other cold highlights include the earliest recorded freeze of the century - September 3, 1974, the coldest September temperature, 22 degrees on September 30, 1974, and the coldest July temperature of the century - 38 degrees on July 30, 1971. The entire decade was not cold, the summer of 1976 had an average temperature of 74.5 degrees which tied for third warmest summer of the century. April 1977 was the fourth warmest of the century with an average temperature of 53.8 degrees. May 1977 was the third warmest May of the century at 66.8 degrees. It also hit 104 degrees on September 6, 1976 which tied for hottest September day of the century. The year of 1976 was warm in general with 55 days reaching at least 90 degrees (2nd most this century). Finally the summer of 1974 had 8 days reach 100 degrees or higher - 4th most for the century.

The decade of the 70s had 247.23 inches of precipitation, slightly below average. The driest year and summer of the century occurred during 1976 with 11.42 inches and 3.86 inches of precipitation respectively. That year also saw the third driest June (1.02 inches). Other dry months include August, 1970 (0.53 inches, 3rd driest) and August 1971 (0.71 inches, 5th driest). September 1974 was the 4th driest of the century with 0.58 inches of rain. The 9.09 inches of rain which fell in August 1975 is the second wettest August of the century. That month also saw the wettest August day this century when 4.59 inches of rain fell on the first. The wettest October day of the century occurred on October 9, 1973 when 4.54 inches of rain fell.

Significant snowstorms for the decade include 11.6 inches on March 19 1970, 12.9 inches on November 21-22 1979, and 12.6 inches March 2-3 1977. One of the worst blizzards of the century occurred January 10-12, 1975. Snowfall with the storm totaled 6.9 inches and high winds combined with falling temperatures to near zero degrees created dangerous low wind chill temperatures that killed numerous livestock in southeast South Dakota and surrounding states. Low visibility and icy roads stranded many motorists. A total of 8 people died in the storm in South Dakota with other deaths in surrounding states. A 2000 foot radio tower east of Sioux Falls collapsed during the storm. A peak wind gust to 69 mph was reported on the 11th with an average wind speed for the day at 37.4 mph. Wind chill temperatures during the day varied from 55 degrees below zero to 65 degrees below zero.


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