ANNUAL CLIMATOLOGICAL SUMMARY
FT. SNELLING MN
The 1829 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.). So far as can be determined, all 1829 observations were taken within the Ft. Snelling enclosure (on the bluffs overlooking the confluence of the Mississippi and Minnesota rivers) .
Analysis of the relationship between 0700, 1400 and 2100 readings indicates that the station thermometer was probably exposed to direct morning and/or afternoon sunlight during at least some portion of the late spring and summer months of 1829. Specifically, 1829 summer temperature records (late May through early August) include numerous 0700 readings exceeding or equaling 2100 readings (thereby reversing or nearly reversing normal summertime diurnal patterns). Such patterns obviously suggest that 1829's warm season average temperatures were elevated by direct exposure to early morning sunlight: the original record indicates, for example, that temperatures averaged about 72 F in June and July 1829 (as adjusted by Fisk, cited below), values which, IF further adjusted for the probable effects of sun contamination , would be reduced to about 71 F.
The foregoing 1829 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 were obtained by averaging statistically derived estimates of 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 1829 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 1829 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.
Although no quantitative precipitation records were kept at Ft. Snelling during 1829, 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 1829 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.
Sunny (twenty four clear days) and dry (snow recorded on only one day) January. Prevailing winds from the west or southwest on eighteen days during January. Sunny (twenty two clear days) and extremely cold February. Readings of -30 F and -27 F at 0700 hours on 9, 11 February, respectively. Snowstorm on 3 February. Prevailing winds from the west or southwest on nineteen days during February. Sunny March (twenty clear days recorded). Warm late March with readings of 46 F at 0700 hours on 27, 28 March and 66 F at 1400 hours on 27 March. Prevailing winds from the west or southwest on eighteen days during March. Sunny (twenty four clear days) and dry April. Very warm late April: readings of 64 F, 70 F and 66 F at 0700 hours on 27, 28, 29 April, respectively . Reading of 84 F at 1400 hours on 28 April. Very warm and sunny (twenty seven clear days) May. Only four days with rain noted during May. Prevailing winds from the south quadrant on most days during May. Temperatures in the 80'F to 90 F recorded at 1400 hours, 28-31 May. Reading of 87 F at 0700 hours on 30 May. Readings of 88 F and 89 F at 1400 hours on 20, 22 May, respectively. Warm, sunny (twenty six clear days) and dry June. Prevailing winds from the south, southwest or west on twenty days during June. Readings of 90 F at 1400 hours on 1, 5 June. Sunny (twenty four clear days) and dry July. Low water levels on the Mississippi river during the summer of 1829, causing delays in delivery of supplies to the Ft. Snelling garrison. Very dry early July: no rain noted between 26 June and 17 July. Sunny (twenty six clear days) August. Very dry late August but some rain (apparently moderate) during early August. Warm late August. Prevailing winds from the west and southwest on seventeen days during August. Cool September. Light frost noted on 14 September. Warm October. Heavy frosts on 20, 25, 26 October. Thirteen cloudy days during October with much cloudy weather noted, 18-24 October. Only four days with rain during October. Prevailing winds from the west or southwest on seventeen days during October. Cold and cloudy (sixteen cloudy days) November. Prevailing winds from the west or southwest on twenty two days during November. Very cold mid-November: readings of -2 F and -6 F at 0700 hours on 19, 21 November, respectively. Readings of 11 F at 1400 hours on 18, 19 November, respectively: 8 F at 1400 hours on 21, 23 November, respectively. Very warm, sunny (twenty one clear days) December. Only four days during December with precipitation noted. Very warm late December. Readings of 38 F at 0700 on 6, 28 December. Reading of 40 F at 0700 on 29 December. Reading of 52 F at 1400 hours on 28 December.
Record indicates that 1829 was a very dry year, probably equaling (or perhaps exceeding) the droughts which occurred during years such as 1863, 1864, 1889, 1910, 1936 and 1976. So far as can be determined, the drought of 1829 began in the summer of 1828 and persisted through much of 1830.