Minnesota (Fort Snelling area) Weather for the year 1824
Cool Spring/Early Summer, Mild December
Extremes of heat and cold were not quite so prevalent during 1824 at Fort St. Anthony, the last full year that it would be known as such. There was a dry winter, a slow spring advance, but an unaccustomedly mild December. Monthly precipitation frequencies continued mostly low, although the summer months’ numbers were at approximately normal levels. Subzero cold was felt as early as mid-November, this followed, however, by the mildest December in the Post’s brief six-year history, the possible effect of a moderate El Nino developing in the far away Equatorial Pacific. Annual mean temperature for the fifth straight year was 43 F.
Almost Snowless Winter – The new year continued where the old one had left off with bright, calm, almost snow-free weather all the way past mid-February. Thirty-seven of the first 46 days of 1824 were “clear”, just four each having precipitation or “fresh”/”high” winds. January (mean temperature: 17 F), mildest in five years’ history, had nearly half its afternoons reaching the 30’s to low 40’s. A week long run of 30 F or warmer afternoons set in over the 22nd, with readings as warm as 42 F and one day thawing in its entirety. But an arctic front on the night of the 30th-31st plummeted the mercury to minus 24 F by morning, just –14 F registered at mid-afternoon of the 31st. February (mean temperature: 13 F) had less than half as many thawing days as January. The winter’s bitterest morning was felt on the 1st, -27 F recorded at 7AM, “fresh” northerlies prevailing during the day. The 4th was also quite cold with –18 F registered at the same hour. Roughly half the remaining mornings were either in single figures above zero or colder, the season’s first significant snowstorm (4 inches) finally coming on the 17th. Two additional light accumulations followed before the close.
Cool Spring – Spring ’24 brought the slowest winter to summer advance in five years, with persistent backward spells in March, April, May, and as well as June. March (average temperature: 24 F), started auspiciously, afternoon temperatures climbing to 53 F on the 2nd and 57 F on the 3rd, both evenings having rains. Hopes of an impending early breakup were quickly set back, though, by an exceptionally raw day on the 8th: minus 5 F recorded at 7AM, 0 F at 2PM, and minus 4 F at 9PM, attended by “fresh” north-westerlies. Two additional arctic outbreaks brought –10 F on the 13th and -1 F on the 20th, the latter day also experiencing a four-inch snowstorm. Grey, gloomy, and chilly weather comprised most of April (mean temperature: 42 F). Nearly half the days were “cloudy”, although there was just six days’ precipitation. Warmest afternoon was 73 F on the 9th, the majority of the other afternoons, however, only in the 30’s and 40’s. The rivers cleared on the 12th, second latest date in five years. Conditions took a backward turn near the close, the 28th just 33 F at 2PM with an inch of snow recorded for the day. The 30th was only 32 F at 7AM. May (mean temperature: 55 F) opened with several more days of frosty weather, freezing temperatures felt on each morning from the 2nd through 5th, afternoon readings on the 1st through 3rd no higher than 44 F. The 3rd was only 27 F at 7AM, even though two hours’ daylight had already elapsed, but no notes of early vegetation damage appeared in the register. Spring up to this point had been too backward for garden plants to be sufficiently forward and vulnerable. The first summery day of the season came suddenly on the 7th with 81 F, the 10th noting 83 F, but most of the succeeding two weeks were cool again, afternoons principally in the 60’s. A three-day rainy spell over the 17th-19th was the month’s only one of consequence. The last two days finished warm, 87 F and 89 F readings, respectively, recorded at 2PM. Sometime between the 13th of this month and the 13th of June, General Winfield Scott, a hero of the War of 1812, visited the Post to conduct its first official inspection. Favorably impressed with the work done in its construction and management, he recommended as a “just complement” to its commander that the name be changed to Fort Snelling, effective next January [Hansen, 1958].
Cool to Pleasant Summer – Summer was considerably more pleasant than last year with only a few hot days and no oppressive spells of note. June (mean temperature: 65 F), the decade’s coolest by a large margin, had nearly half its afternoons in the low 70’s or cooler. Thirteen days recorded rain. The 6th reached 85 F for the month’s highest, but the second week and most of the third were decidedly cool, the majority of the afternoons in the 60’s. A few 7AM readings were read in the low 50’s, indicative of overnight minima well down in the 40’s considering that dawn had broken some 2 1/2 hours earlier. An astronomical occurrence of note was recorded on the 26th with “a partial eclipse of the sun at 6PM.” July (mean temperature: 72 F) brought predominantly seasonable temperatures for the first time this year. Just three afternoons reached 90 F, the hottest day of the summer, 96 F, coming on the 8th. Nine days had rain. August (mean temperature: 70 F) was similarly pleasant with only one afternoon as warm as 90 F and eight days with rain. A semblance of a muggy spell developed in the middle of the second week, five days in succession reaching the mid-to-upper 80’s, but just one reading as warm as 80 F was recorded after the 15th. Afternoons over the final week were generally in the upper 60’s to low 70’s.
Long Dry Spell, Early Arctic Cold, Then Mildness – The remaining months of 1824 brought a three-and-a-half week dry spell over September and October, an unseasonably early arctic outbreak in November, but unaccustomed mildness over virtually all of December. September (mean temperature for the month: 61 F, five total rain-days) opened cool, afternoon temperatures confined to the 60’s on five successive days over the 4th-8th. Frosts were noted for the 6th and 7th. Behind several straight days of “fresh” to “high” south to southeasterly winds, unseasonably warm and humid weather then set in near the end of the second week. Daily temperature range on the 13th was a sultry 70 F to 84 F with the 14th’s a similar 68 F to 80 F. Three of the next four days had thunderstorms, and the mercury reached 80 F on the 20th, but a drier and cooler turn then followed, diurnal ranges for the balance of the days confined to the low 50’s for the mornings and the 60’s for the afternoons. October, cool (mean temperature: 44 F) and grey (18 “cloudy” days) had only four precipitation-days. Most afternoons over the first three weeks were in the 50’s and 60’s, highest of the month, a relatively cool 68 F, coming on the 9th. Nights after this date were generally freezing or near freezing, several morning readings dropping into the mid-to-high 20’s. The month’s first rain, coming on the 19th, broke a 24-day dry spell. From this date through month-end, “Cloudy” conditions ruled, most afternoons in the 30’s and 40’s, the 28th quite cold and blustery with 26 F at 7AM and 34 F at 2PM, accompanied by “high” northwesterlies. November (mean temperature: 30 F) was mostly dull and cloudy with premature subzero cold shortly after mid-month, followed by a significant warming. Altogether there were 22 “cloudy” days and ten days’ precipitation, most of the latter light snows. Daily temperatures into the second week were monotonously chilly with slight diurnal ranges, mornings mostly in the 20’s, afternoons in the 30’s. Ice was seen in the Mississippi as early as the 8th. A premature arctic outbreak, the earliest yet in Post experience then followed. Subfreezing weather was experienced continuously over the 14th-19th, and minus 1 was recorded on the morning of the 17th, earliest subzero temperature reading here for another 24 years. An early-season harbinger of a long winter to come had seemingly been presented, but in a surprising turnabout, a steady warming trend ensued, temperatures trending upward to the 50’s by the 29th. The Mississippi, having been shut with ice at mid-month, was clear again from the Post vantage point. The 30th was the mildest day since early October, thundershowers and lightning occurring during the morning and evening, strong southerly winds driving the mercury to 57 F by 9PM. December (mean temperature: 22 F) was the mildest such month in six years, most afternoons reaching the high 20’s to the 30’s, no subzero temperatures read at 7AM nor any “fresh” or “high” wind days noted. Twenty-one days were “cloudy”, several light snows being the only precipitation falls. The Mississippi finally closed for the winter on the 12th, latest such date in the brief period of record. More unusual climatic “surprises” would come over the opening months of 1825.