National Weather Service Weather Forecast Office

Sioux Falls record highest and lowest air pressures
in inches mercury (adjusted to sea level) by month
...period of record 1948 to 2009

month  highest  date            lowest  date

Jan     31.04 10th 1962         29.05 10th 1980
Feb     31.06  3rd 1989         28.97  9th 2009
Mar     30.98 11th 1998         28.63 26th 1950
Apr     30.78 14th 1981         28.85  7th 2001
May     30.55  7th 1959         28.77  5th 1950
June    30.47  8th 1980         29.00 25th 1969 and 7th 2007
July    30.45  4th 1972         29.35  3rd 1993
Aug     30.55 31st 1967         29.36  3rd 1980
Sept    30.58 23rd 1989         29.23 22nd 2006
Oct     30.79 18th 1989         28.77 10th 1949
Nov     30.90 12th 1986         28.91 10th 1998
Dec     31.08 22nd 1989         28.90 17th 1967

annual  31.08 12/22/1989        28.63 3/26/1950

Sioux City record highest and lowest air pressures
in inches mercury (adjusted to sea level) by month
...period of record 1900 to 2009

month  highest  date            lowest  date

Jan     31.09 25th 1905         28.96 15th 1943
Feb     31.07 21st 1918         28.89 23rd 1977
Mar     30.83  4th 1948         28.66 26th 1950
Apr     30.75 14th 1981         28.87  2nd 1982
May     30.55 25th 1901         28.84  5th 1950
June    30.47      1913         29.08  2nd 1943
July    30.43  4th 1972         29.29  9th 1926
Aug     30.53 31st 1967         29.43 30th 1956
Sept    30.67 25th 1926         29.20 22nd 2006
Oct     30.83  8th 2000         29.05 10th 1949
Nov     30.96      1911         28.85 10th 1998
Dec     31.09 29th 1917         28.91  6th 1951

annual  31.09 1/25/1905         28.66 3/26/1950
         and 12/29/1917

RYRHOLM 2/18/09