FT. SNELLING MN
The 1822 Ft. Snelling climatological record consists of fixed time temperature readings taken daily at or about 0700, 1400 and 2100 hours local solar time; single daily entries indicating the prevailing direction of the wind and the general condition of the sky; intermittent records of snowfall and/or snow cover; episodic records of phenological, hydrological, astronomical and/or other natural events (windstorms, prairie fires, etc.); descriptive entries indicating the general duration (and, in some instances, the intensity) of precipitation; precipitation type ; and special atmospheric phenomena (fog, smoke, etc.). Observations during 1822 may have been taken within the permanent fort enclosure (on the bluffs overlooking the confluence of the Mississippi and Minnesota [then the St. Peters] rivers) or, alternatively at Cantonment New Hope (a temporary camp consisting of log huts constructed in 1819 in the bottomlands adjacent to the St. Peter's [Minnesota] river) and/or at Camp Coldwater (a temporary summer camp site on the upland prairie about one mile northwest of the site of the permanent fort) .
To the extent that they may have been obtained from instruments exposed in the Minnesota river bottomlands, 1822 temperature values may be significantly lower than values which would have been obtained (ceteris paribus) from thermometers located at the Ft. Snelling or Camp Coldwater sites (both of which are significantly higher than the bottomlands site). Whatever its location, analysis of the relationship between 0700, 1400 and 2100 readings suggests that the station thermometer was probably not exposed to direct afternoon or morning sunlight at any time during 1822. This suggests, in turn, that 1822 temperature records (in contrast to some averages for prior and subsequent years) were not significantly distorted by direct exposure to sunlight: 1822 average temperatures, accordingly, require no "sun pollution" adjustment. The foregoing 1822 temperature record includes both unadjusted (UNADJ) and adjusted (ADJ) mean temperatures. Unadjusted values are the averages of fixed time readings taken daily at 0700, 1400 and 2100 hours . Adjusted averages are from Charles J. Fisk's 1984 "Reconstruction of Daily 1820-1872 Minneapolis-St. Paul Temperature Observations". These values are based on statistically derived estimates of the daily maxima and minima that would have been recorded had the Ft. Snelling station been equipped with self-registering thermometers read and re-set at midnight . The foregoing 1822 record also includes both the monthly and annual extreme temperatures (highest daily minimum, lowest minimum, etc.) estimated by Fisk and the monthly extremes actually recorded/observed (OBSRV) by fort observers. All 1822 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.
For reasons not indicated in surviving records, fort observers failed to take (or record) temperature readings on 13 and 15-16 July 1822. This break in the record has been filled by Fisk (op. cit.) with regression derived estimates of absolute maxima and minima for those dates, using 1822 temperature records from the U.S. Army's station at Ft. Crawford (Prairie du Chien) WI.
Although no quantitative precipitation records were kept at Ft. Snelling during 1822, extant records do, as noted, contain entries indicating precipitation type and, in some instances precipitation intensity (e.g. light snow, heavy rain, etc.). These records are the basis of the foregoing 1822 precipitation frequency record (e.g. number of days with snow, etc.) . Prevailing wind values, similarly, are based on entries indicating the predominate direction of the wind on each day of the month. Prevailing monthly winds indicate the direction most frequently observed/recorded during any given month.
Very cold early January: -25 F at 0700 hours on 4 January. Mid-month warm-up: 46 F at 1400 hours on 21 January. Rain on 17 January "accompanied by a very unexpected change in the weather from a very cold to a very moist atmosphere with winds...from the south...". Winter snow cover noted as having "almost disappeared" in mid-January. Eighteen days during January recorded as "cloudy". 38 F at 0700 hours on 31 January. Cold early February with much warmer conditions after 10 February. Warm March: 60 F at 1400 hours on 4 March and 68 F at 1400 hours on 16 March. Five inches of sleet and snow on 26 March. Cloudy (sixteen cloudy days) April: cold at mid-month with readings of 19 F at 0700 and 30 F at 1400 hours on 14 April Four inch snowfall on 10 April. Readings in the 80's F at the close of the month. Wet May with damaging frosts in low lying areas on 21-23 May. Excessively wet June with several "very heavy" thunderstorms noted. Flooding on the Minnesota and Mississippi rivers. Much sickness among garrison personnel during June: attributed to "excessive inclemency" of the weather. Twenty days recorded as "cloudy". Sunny (twenty two "clear" days) and warm July. Warm and sunny (twenty six clear days) August. Light frosts, 2-4 September. Warm late September: 83 F at 1400 hours on 24 September. Windy October. "Heavy gale of wind" followed by prolonged rainfall on 5-6 October. Cold late October: 15 F at 0700 hours on 24 October. Twenty three "clear" days recorded during October. Warm early November with heavy rainfall. Extreme cold late November: 6 F at 1400 hours on 29 November; -23 F at 0700 hours on 30 November and 3 F at 1400 hours on 30 November. Cold preceded by heavy snowfall. Record cold December: temperatures near -30 F during the first week of the month. Reading of -12 F at 1400 hours on 2 December. Short warm-up on 9-12 December followed by intense cold which persisted during much of the remainder of the month. Heavy snowfall on 15 December. Reading of -29 F at 0700 on 23 December.