Graphical Climatology of Minneapolis-St. Paul Area Temperatures, Precipitation, and Snowfall (1820 – Present)
By Charles Fisk*
Last Update: 4 Jan 2013
Note: Website is in process of redesign. No updates until completed.
     The following is a graphical climatology of Minneapolis-St. Paul, Minnesota temperatures, precipitation, and snowfall, from the start of 1820 (Fort Snelling) through 2012. Presented are summary overview charts, a link to a year-by-year account of early (1820-1869) Minnesota weather history, followed by year-to-year graphs depicting daily temperatures, precipitation, and snowfall. Original source data are from Fort Snelling (1820-1858), St. Paul Smithsonian recordings (1859-1872); and government weather service observations for St. Paul (1873-1890), downtown Minneapolis (1890-1938), and the Minneapolis-St. Paul International Airport (1938-present). Daily snowfall totals date from 1891, snow depth data from 1893.
Data were obtained from the National Archives, the Minnesota Historical Society, The University of Minnesota Periodicals Library, the National Climatic Data Center, the Minneapolis-St. Paul National Weather Service Office online site, and the Minnesota Climatology Working Group. Monthly updates are from the site: http://climate.umn.edu/doc/prelim_lcd_msp.htm
CLIMATE OVERVIEW GRAPHS
TEMPERATURE:
MINNEAPOLIS-ST. PAUL DAILY TEMPERATURE MEANS & EXTREMES (FOR 1873-2011)

YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC   

OTHER MINNEAPOLIS-ST. PAUL DAILY TEMPERATURE STATS:

MINNEAPOLIS-ST.PAUL AVG DAY-TO-DAY VARIABILITIES, STANDARD DEVIATIONS, AND SKEWNESS STATISTICS in DAILY MEAN, MAX, & MIN TEMPS, BY CALENDAR DAY
MINNEAPOLIS-ST. PAUL AVERAGE DAILY TEMPERATURE RANGES, BY CALENDAR DAY
MINNEAPOLIS-ST. PAUL YEAR-TO-DATE 2012 MEAN TEMPERATURE VERSUS RECORD WARM 1931 & 2ND WARMEST 1987     **

ANNUAL MEAN TEMPERATURE HISTORY GRAPH:

MINNEAPOLIS-ST. PAUL ANNUAL MEAN TEMPERATURE HISTORY (1820-2012)   **

PRECIPITATION:       

MINNEAPOLIS-ST. PAUL YEARLY PRECIPITATION HISTORY (1859-2012)     **   
MINNEAPOLIS-ST. PAUL AVERAGE MONTHLY PRECIPITATION (1871-2008)
MINNEAPOLIS-ST. PAUL PRCP-DAY FREQUENCIES FOR >=0.01″, >=0.13″, >=0.25″, >=0.50″, & >=1.00″ MAGNITUDES, BY CALENDAR DAY (1891-2007)
MINNEAPOLIS-ST. PAUL YEAR-TO-DATE PRECIPITATION FOR 2012 VS. LONG-TERM AVERAGE AND RECORD WET 1911/DRY 1910    **       

SNOWFALL:

MINNEAPOLIS-ST. PAUL SNOWFALL FOR 2011-12        
MINNEAPOLIS-ST. PAUL SEASONAL SNOWFALL HISTORY (1884-85 THRU 2011-12 SEASONS)       
MINNEAPOLIS-ST. PAUL AVERAGE MONTHLY SNOWFALL
MINNEAPOLIS-ST. PAUL ONE-HALF, ONE, TWO, AND THREE-INCH SNOW-DAY PROBABILITIES, BY CALENDAR DAY
MINNEAPOLIS-ST. PAUL MEDIAN, MEAN, AND EXTREME MAXIMUM SNOW DEPTHS, BY CALENDAR DAY
ESTIMATED ST. PAUL SEASON-TO-DATE SNOWFALL FOR 1880-81 (THE GREAT “SNOW WINTER”)

ARTICLES:

“A Multivariate Analysis of Summary-of-the-Day Snowfall Statistics vs. Same-Day Water Precipitation and Temperature Recordings” – American Meteorological Society 17th Conference on Applied Climatology – Whistler, B. C., Canada, 2008. http://ams.confex.com/ams/pdfpapers/141141.pdf (Estimates Seasonal Snowfall for great “Snow Winter” of 1880-81: ~ 140 inches)

MONTH/HOUR CLIMOGRAMS:

MEAN HOURLY TEMPERATURE/HUMIDITY
THUNDERSTORM FREQ
WINDS
FOG/HAZE
FLYING WEATHER/CEILINGS

YEAR-BY-YEAR ENCYCLOPAEDIC ACCOUNT OF EARLY MINNESOTA WEATHER (1820-1869)
THE MINNEAPOLIS-ST. PAUL AREA TEMPERATURE RECORD: OFFICIAL WEATHER BUREAU OBSERVATIONS (1873-PRESENT) AND RECONSTRUCTED PIONEER ERA RECORDINGS (1820-1872)
Temperature graphs for the 1873-present period are based on official St. Paul or Minneapolis daily absolute maximum and minimum temperature observations (nearly all for the midnight-to-midnight hourly interval), the standard method of recording “summary-of-the-day” temperature statistics for first-order weather stations.
However, original summary-of-the-day temperature observations for the 1820-1872 “Pioneer” era (along with those for cloudiness, wind direction, and wind force) consisted of fixed-time scheme observations conforming to some prescribed format (e.g., 7AM, 2PM, and 9PM; or Sunrise, 9AM, 3PM, and 9PM; or others).
For methodological consistency, the 1820-1872 temperature observations were converted into midnight-to-midnight absolute maxima and minima estimates, using application of 1961-1980 statistical regression relationships between Minneapolis-St. Paul Airport temperature, cloudiness, and wind information at hours corresponding to the old fixed-scheme times, and 1961-1980 midnight to midnight absolute daily temperature maxima and minima [Fisk, 1984]. This reconstruction created reasonable approximations of the Pioneer era daily midnight to midnight maxima and minima, and in addition to reducing biases in (recalculated) 1820-1872 monthly mean temperatures, allowed for daily maximum/minimum temperature graphs to be constructed, as is done here, for every year of the history.- 1820 to the present.
DETAILS ON RECONSTRUCTION OF MINNEAPOLIS-ST. PAUL AREA 1820-1872 TEMPERATURE RECORD.
YEAR-TO-YEAR GRAPHS – INTERPRETATION
For a given year’s graphical display (see links below), the uppermost chart is a “floating-bar” chart of the daily maxima and minima. Superimposed are two line traces, the upper one connecting average daily maxima, the lower one average daily minima. The bars depict the varying diurnal, synoptic, long-wave, and seasonal influences on temperature over time, and subjectively, some years’ patterns can be quite interesting to look at (see “LINKS TO SOME OF THE MORE INTERESTING YEARS WITH ACCOMPANYING NOTES” section below).
The second chart down depicts the arithmetic departures of day-to-day mean temperatures (sum of the daily maximum plus the daily minimum divided by two) less the corresponding calendar-day average means. Vertical lines extending upward from the zero line indicate above average means for the day (colored red), those extending downward indicate below average daily means (colored blue). In the entire series of nearly 70,000 days, greatest positive departure for any individual day is +40 F on 17 & 18 March 2012, the greatest negative departure -45 F for 1 January 1864.
1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
The third chart down shows chart two’s departures in deseasonalized or “standardized” form. This adjusts for the fact that individual calendar days have higher or lower inherent year-to-year variability (standard deviations) in daily mean temperature. Dividing a given day’s departure from average by its’ respective calendar day mean temperature standard deviation creates the “relative” departures or “z-scores”. Only five daily departures in the entire series are plus or minus 3.5 or greater. Three of these, all negatives, came over the four-day period 4-7 November 1991, associated with an unseasonably cold arctic air outbreak in the wake of the Great 1991 Halloween snowstorm. The fourth chart down depicts daily rainfall, the fifth and sixth charts, respectively, daily snowfall and snow depths.
LINKS TO SOME OF THE MORE INTERESTING YEAR-TO-YEAR GRAPHS, WITH ACCOMPANYING NOTES

1820 – Year One. Frigid January WEATHER DIARY FOR JAN 1820, very mild April, eleven-inch snowstorm in mid-October. 1820 Writeup.
1822 – Coldest December in history DEC 1822; December 2nd 42 F below average. Also torrential June rains, producing local flooding JUN 1822. 1822 Writeup
1824-1825 – (July-June view). Exceptionally mild December ‘24 to April ’25 period; likely El Nino influence. 1825 Writeup
1826 – Very backward April APR 1826 (accompanied by severe flooding), but May 28 F warmer than April. 1826 Writeup
1829 – “The Dry Year”, as described by early Minnesota history texts. Severely cold February and other extreme temperature spells throughout year. 1829 Writeup
1830 – Hottest July until 1936, and much above normal October/November. 1830 Writeup
1833– El Nino winter of ‘32-’33 mildest for another 45 years. Very mild December ’33 also. 1833 Writeup
1833-34 – (July-June view). Greatest three-month thermal “see-saw” in history: January 1834 29 F colder than December 1833, February 1834 28 F warmer than January. 1834 Writeup
1835 – Volcanic dust-veil produces series of anomalous cold spells during second half. 1835 Writeup
1838 – Great temperature extremes. Minus 40 F in February and a late May hard freeze. Hot summer, but unseasonable cold in fall and early winter. 1838 Writeup
1838-39 – (July-June view). Abnormal cold over October to December ’38 gives way to abnormal warmth over January to April ‘39.
1839 – Warmest recorded year up to this time; warmest April APR 1839 down to the present day. 1839 Writeup
1842 – Extraordinary coolness over mid-May into July. Coldest June JUN 1842 and coldest November NOV 1842 in all history down to present. 1842 Writeup
1843 – Coldest year in area history. Extraordinary persistent arctic cold over February and March. Coldest March (more than 25 F below average) MAR 1843, and coldest October OCT 1843 in all history down to present. 1843 Writeup
1842-43 – (July-June view).
1845 – Steep temperature plunge over mid-to-late November. 1845 Writeup
1846– Warmest year of pre-statehood era. Mildest January in all history down to the present JAN 1846. 1846 Writeup
1849 – December 34 F colder than November. 1849 Writeup
1855-56 – Two successive arctic blasts, in late December DEC 1855 and early January JAN 1856. A third in February. 1856 Writeup
1857 – Second successive bitter winter. Coldest January JAN 1857 and April APR 1857 in history. 1857 Writeup
1863 – The “Strange” weather year. Extremes in temperatures, and worst growing season drought to date – no measurable rain in June (St. Paul). Killing frosts in July and August across settled areas. 1863 Writeup
1864 – Continued drought during the year. Frigid New Years’ Day – Maximum: -24 F, Minimum: –38 F in St. Paul. 1864 Writeup
1865 – Heavy summer rains break drought; 38” recorded for year in St. Paul, more than ’63 and ’64 combined. Very cool summer, July 1 F cooler than September. 1865 Writeup
1867 – Very backward spring. March 1867 5 F colder than any March since, but still 8 F milder than 1843. More than 10” rain in June in St. Paul. 1867 Writeup
1869 – More than 18” rain over August and September. 1869 Writeup
1875 – Second coldest year in history. January and February both AVERAGE below zero.
1877-78 – “Year Without a Winter”. El Nino-induced extraordinarily mild winter. Mildest December in history. Warmest February until 1931 and warmest March until 1910.
1879 – “Second Edition of Summer” brings unseasonable October warmth. Very cold Christmas Day, minus 39 recorded in St. Paul.
1885 – Great temperature variability over January to March.
1888 – Severe winter (including –41 F in January). Persistent spells of unseasonable coolness into spring and summer.
1895 – Abrupt May cold turn temporarily derails an otherwise forward Spring.
1899 – Great February cold wave.
1907 – Persistent abnormal cold through April and May; 13” snowstorm over Apr 27-28.
1910 – Driest year (11.54”) in local climatic history down to present. Also warmest March in history until 2012.
1911 – Great adjacent-year reversal in annual precipitation – Wettest year (40.15”) in all history down to present.
1915 – Very forward April, but May 4 F colder; very cool summer ensues.
1917 – Coldest year of 20th Century. Deep Snows – 31” depth on 16 March.
1921 – Warmest year since 1878.
1923 – Very cold March, very mild November-December.
1930 – Sharp temperature gyrations over latter part of year.
1931 – Warmest year in history down to the present; 104 F recorded in September.
1933 – Warmest June in history. 77 F on 1 November
1934 – In midst of Dust Bowl era. Warmest May in history, including 106 F on the 31st. June has a 104 F day, three days in July reach 105 F.
1936– Great temperature contrasts between winter and summer. Thirty-six consecutive days with subzero minima over January and February (including –34 F in January). Hottest July on record; 108 F recorded on 14th for highest in history. Also recorded in July: 106 F three times, 105 F and 104 F once day each.
1940 – Great Armistice-Day Blizzard leaves nearly 17 inches’ snow over 11th-12th.
1942 – Very irregular temperature anomaly pattern over course of year.
1945 – Very forward early spring, then very cool through early summer.
1947 – Warmest August AND October in all history down to the present.
1948 – March temperature range –27 F to 70 F (97 F spread highest ever for a single calendar month locally).
1951 – 40” snowfall in March.
1953-54 – Quasi-periodic much above normal spells over late-August through February. February ‘54 warmest since 1878.
1958 – Driest year (16.20”) since 1910.
1959 – December 5 F warmer than November.
1962 – Deep snows in late February and early March; minus 32 F on 1 March.
1965 – Coldest March since 1899; coldest September since 1868.
1967 – 35.3” snowfall in January; 30” snow depth on 19 February.
1972 – Coldest year since 1917.
1976-77 – Twentieth century approximate version of 1838-39. Abnormally cold October-January, unusually warm February-May.
1982 – 46.4” snowfall in January, 38” snow depth on 23 January. 1981-82 season sets new snowfall record (95.0”) – only to last two seasons, however.
1983– Great El Nino year. Wettest year (39.07”) since 1911. Very mild January to early March, a warm summer, but coldest December since 1831. 21.8” snowfall in April – a new high mark for that month.
1983-84 – Snowiest winter in official recorded history (98.4”).
1985 – Unusually mild March and April, cold November-December.
1987 – Second warmest year in history. Steady above average warmth throughout virtually the whole year. July wettest calendar month in local history (17.90”).
1988 – Drought year. Very hot summer, 105 F in July.
1991 – Great early snowstorm drops 27” over 31 Oct and 1 Nov followed by unseasonably early arctic outbreak; 46.9” total snowfall for November, snowiest calendar month in recorded history.
1992 – Very mild winter. Very cool summer (possibly induced by Mt. Pinatubo eruption); Coolest July since 1865.
1996 – Great arctic outbreak in late-January/early February.
1997-98 – El Nino-induced, very mild ‘97-‘98 winter.
2000 – Very mild March, very cold December.
2001 – Wettest April on record (7.00”). Warmest November in history by more than 4 F. Fifty-seven consecutive above normal temperature days from late October to late December.
2001-02 – Mildest November-February period in all history by nearly 2 F.
2006 – Third warmest year in all history. Warmest January since 1846; warmest July since 1936.
2010 – Warmest August since 1947 and second warmest in history.
2012 – Warmest March in history by more than 3 F.

*Member, American Meteorological Society