ANNUAL CLIMATOLOGICAL SUMMARY
FT. SNELLING MN
The 1856 Ft. Snelling climatological record consists of: a) temperature and hygrometric readings taken daily at 0700, 1400 and 2100 hours; b) wind direction and wind force readings taken daily at 0700, 1400 and 2100 hours; and c) descriptive sky cover observations (expressed, as before 1843, only as "cloudy" or "fair") taken daily at 0700, 1400 and 2100 hours. So far as can be determined, 1856 Ft. Snelling precipitation observations were taken either at 2100 hours or in the early morning (probably at or about 0700 hours, at the time of the first daily temperature observation). As in prior years, some precipitation values (particularly those which might have been obtained from early morning readings) may have been "shifted" from the date on which the observation was actually made to the day immediately preceding.
So far as can be determined, 1856 Ft. Snelling temperature readings were taken from an instrument manufactured by George Tagliabue, New York City and precipitation observations were taken from a DeWitt conical rain gauge mounted on a pole or post on the fort's parade ground . Fixed time temperature readings taken by Ft. Snelling observers during 1856 appear to be consistent with normal diurnal patterns (indicating that the station thermometer was, for the most part, located/sheltered as necessary to protect it from exposure to direct sunlight). All 1856 wind force values are expressed in terms of a numeric wind force indicator selected by fort observers after visually noting the effect of wind on flags, trees, signs and other easily movable objects . As noted, 1856 sky cover values are expressed descriptively as "cloudy" or "fair", terms which, so far as can be determined, indicated either that the sky was more than 50 percent obscured by clouds (designated as "cloudy") or less than 50 percent obscured (designated as "fair").
Like corresponding records from the years immediately preceding, the 1856 Ft. Snelling record appears to significantly understate the number of days with precipitation and/or measurable precipitation. This suggests that -- following the example of their predecessors -- Fort observers did not routinely/consistently measure and/or record small precipitation events, sometimes either ignoring less significant deposits of rain or snow (or. alternatively, using terms such as "inappreciable", "unmeasurable" or "slight" to denote small, but perhaps otherwise measurable, amounts of precipitation). This tendency is particularly evident in records for the winter months of year: St. Paul newspaper accounts -- together with contextual evidence from the 1856 record itself -- suggest, in fact, that Fort observers, for whatever reason, sometimes failed to measure or record significant portions of the precipitation which fell during the winter months (and, to a lesser extent, probably the summer months as well).
Although the 1856 Fort Snelling record includes daily liquid/melted precipitation values and a record of the TYPE of precipitation observed, it contains NO QUANTITATIVE snowfall values (whether of fresh snowfall or accumulated snow cover). Therefore, unless otherwise noted, snowfall values contained in the foregoing compilation are estimates inferred from newspaper accounts of 1856 snowfall events and/or obtained by applying the National Weather Service meltwater-snowfall conversion matrix to the meltwater values recorded by Ft. Snelling observers on 1856 "snow days".
The foregoing 1856 climatological record includes both unadjusted (UNADJ) and adjusted (ADJ) mean temperature values. Unadjusted values were calculated by taking a weighted average of the station's 0700/1400/2100 fixed time readings. Adjusted averages are from Charles J. Fisk's 1984 "Reconstruction of Daily 1820-1872 Minneapolis-St. Paul Temperature Observations". These values were obtained by averaging statistically derived estimates of the daily maxima and minima which would have been recorded had the Ft. Snelling station been equipped with self-registering thermometers read and re-set at midnight. The foregoing 1856 record also includes both the monthly and annual extremes (e.g. highest daily minimum) estimated by Fisk and the monthly extremes actually recorded by fort observers, All 1856 temperature distributions (e.g. days 90 F or higher, 32 F or lower, etc.) are based on Fisk's estimates of daily maxima and minima. All foregoing monthly mean force of wind values are the simple average of the station's fixed time sky cover and air movement observations. The foregoing prevailing wind values are based on fixed time wind direction observations: prevailing/predominate winds are those most frequently observed/recorded during any given month.
In addition to the Ft. Snelling record, the 1856 east central Minnesota climatological record includes records kept by several St. Paul pharmacists. These records have survived in fragmentary form and only to the extent published in pioneer era St. Paul newspapers.
Very cold, snowy January: readings of -27 F, -31 F, -32 F, -32 F and -25 F at 0700 on 3, 7, 8, 9, 10 January, respectively. Readings of -12 F, -14 F, -10 F and -10 F at 1400 on 7, 8, 9, 10 January, respectively. Reading of -38 F recorded by St. Paul observer W. H. Morton at 0600 on 8 January. St. Paul newspaper [21 January] noted that "...the weather during the winter has been unusually severe throughout the country...in St. Paul, we have experienced extreme cold...the snow on the ground..is about eighteen inches deep but has not drifted to any great extent owing to the absence of high winds...". Cold, dry February. Readings of -27 F and -31 F at 0700 on 3, 4 February, respectively. Thawing conditions on many days in late February. Dry and very cold March: readings of -16 F, -15 F and -10 F at 0700 on 9, 10, 12 March, respectively. St. Paul newspaper accounts indicate that the Mississippi river was solidly frozen as late as 28 March. Wet, windy April: force eight winds on 12, 27 April; force seven winds on 1, 16, 17, 25 April. Many days with force five and force six winds. Prairie fires noted on 8, 10 April. Rising river levels noted during April. Warm, sunny, dry and windy May: force eight winds on 5, 23 May. Afternoon readings in the 80's to low 90's F each day, 19-23 May. Severe thunderstorm in St. Paul on 24 May. Warm, sunny, very dry June. Reading of 95 F at 1400 on 23 June: 96 F recorded at Morton's site at 1600 on the same date. Hot, sunny July. Readings of 95 F at 1400 on 16, 22, 23 July. Readings of 100 F, 99 F, 99 F and 98 F at Morton's St. Paul site at 1200 hours on 22, 23, 24, 25 July, respectively. Low water levels with impeded navigation on the Mississippi river noted during July. St. Paul newspaper [24 July] stated that "..the weather for the past few days has been excessively warm..nay, it has been hot, the mercury making 103 degrees in the shade and the earth almost weeping for rain....". Cool, dry August. Severe thunderstorm in the Ft. Ridgely area on 2 August: hailstones up to one-half pound reported. Drought related crop damage noted in early August. Two inch rainfall accompanied by "hurricane force" winds on 16 September. Cool late September: killing frost noted on 20 September, Windy, cold and wet conditions on the closing days of September (St. Paul newspapers noted that "...overcoats and shawls have been brought into requisition in great numbers..."). Warm, cloudy and wet October; 2.9 inches of rain recorded at Ft. Snelling, 21-22 October. Windy conditions noted on many days during the month. Reading of 85 F at 1400 on 7 October. Outbreak of prairie fires with extensive damage in mid-October. St. Paul Pioneer (15 October) reported that "..last evening the prairies around our city in different directions were on fire and the sight was a most beautiful one...". Violent thunderstorm in St. Paul on 21 October. Very windy, dusty conditions noted in St. Paul for "four or five days" prior to the storm. Brief cold wave early November: reading of 5 F at 0700 on 8 November. Snow cover of four to five inches reported at the end of November. Cold, very snowy December: readings of -20 F at St. Paul's Day and Jenks pharmacy at 0600 on 7, 15 December. Snow cover of twelve to fifteen inches reported in St. Paul at the end of December.