Minnesota (Fort Snelling) weather for the year 1834
Continued Mostly Above Normal Temperatures, A Wet Summer
The above normal temperature regime prevailed for yet another year at Fort Snelling during 1834, but in a major pattern shift, generous growing season precipitation was received. Annual mean temperature (46 F) was a degree cooler than last year, attributable mostly to a bitterly cold January, second coldest calendar month here in 15 years. Spring, however, like most of the others so far this decade, brought unseasonably forward warmth, and similar to a year ago, November also displayed uncommonly mild and fine weather.
A Great Thermal Flip-Flop – January and February ’34 completed the greatest three-month monthly mean temperature oscillation in the entire climatic record down to the present. The former (mean temperature: 2 F) was 29 F colder than December, the latter (mean temperature: 30 F) 28 F warmer than January. January’s character was set over the very first days as a great reservoir of extremely cold arctic air, the first signs of which just were beginning to be felt on New Year’s Eve, swept over the area. Bitter morning temperatures of -27 F, -29 F, -32 F, and -31 F were read on the 2nd through 5th, respectively, the minus 32 F figure tying the mark set on 24 January 1821 for “the greatest degree of cold here”. Temperatures were frigid over much of the month, just four days reaching the 30’s (highest 40 F). A couple of shorter-lived arctic pulses brought a -19 F reading over the second week and -19 F and -26 F recordings over the third. Nineteen “fair” days were recorded, four had snow, and one had rain. Describing his first January at Fort Snelling in a letter to his sister dated 2 February, Surgeon N. S. Jarvis wrote: “… we have all have been most of the month shut up in the fort and confin’d to our rooms owing to the excessive cold…” [Ziebarth & Omisky, 1970]. February, however, was the warmest on record thus far, one that would have passed as an average March, thermally. The day after Jarvis completed his letter, an eight-day spell with afternoon temperatures in the 40’s to low 50’s suddenly set in, accompanied by mostly “fair” skies and south to southwesterly winds. Weather over the remainder of the month stayed unseasonably mild, all but three of the afternoons at least 30 F, with just a single near zero morning felt on the 16th (1 F). Two snows over the final week comprised the month’s only recorded precipitation.
Mild, Dry Spring – Spring, for the third successive year, brought consistent spells of unseasonably forward temperatures along with infrequent precipitation falls. Precipitation-day tally for January-April (15) was the least since drought-year 1829 (also 15). March (mean temperature: 32 F) had its share of unseasonable mildness but not to the degree or extent as February. Most afternoons through mid-month reached at least the 40’s, eight out of nine beginning with the 10th in the upper 40’s to mid-50’s. Highest (55 F) came on the 10th. A backward turn then followed, eight days in succession from the 20th confined to the 20’s and 30’s, the month’s coldest temperature (9 F) registered on the 26th. No notes of the Mississippi’s opening appeared, but it seems likely with all the early mild weather that another March event must have been witnessed. April (mean temperature: 50 F) was the fourth in five years with a mean temperature of 50 F or better, a feat not repeated in the local climatic record since. Spring quickly resumed its robust advance on the 3rd with commencement of a two-week warm and dry spell. Through the 17th, afternoon temperatures reached the upper 60’s or higher almost each day, all but one of them “fair”, with no rain noted. Highest temperature of the month (80 F) was recorded on the 15th. With incipient drought signs no doubt evident at this point, a bit of relief followed with four rain-days over the 18th-22nd, accompanied by a marked cooling. Afternoon readings over the 18th-26th got no warmer than the 40’s and 50’s, the latter day only 32 F at 7AM and 42 F at 2PM. May (mean temperature: 60 F) featured pleasant to cool weather over the first half succeeded by an extended warm and humid spell extending into the final week. Nine rains were experienced, most of these over the last ten days. Afternoon temperatures through the 15th were seasonable to cool, mostly in the 50’s and 60’s, another brief rainy period with four falls in five days coming over the 4th-8th. Starting on the 16th, however, an unseasonably warm term set in, lasting eleven days. Afternoon readings from the 18th reached the 80’s eight out of nine times, including 90 F on the 22nd, 88 F on the 25th, and 87 F on the 26th. A preview of June, the month went out wet and cool, four out of the last five having rains, the 28th only 48 F at 2PM, the 29th, 54 F.
Cool and Wet June, Hot July – Summer ’34 brought a definitive end to the six-year run of rain-infrequent summers, June-August combined rain-day tally (34) the highest in fifteen years of record. June had sixteen rains, most of any calendar month thus far in fifteen years, steady coolness also felt with only a few afternoons passing the mid-70’s and a large number confined to the 60’s. Monthly mean temperature (65 F) tied 1824 for lowest in fifteen years. July, in contrast, was the second warmest since ’20 (mean temperature: 76 F), 29 “fair” days and eight rains recorded. A long hot spell, destined to extend into early August, made up the last 12 days, afternoon temperatures almost exclusively in the upper 80’s to mid-90’s, the highest (94 F) noted for both the 21st-22nd. Diary notes for the 8th reported “heavy thunder at 3AM accompanied with incessant lightning and storm of hail destroying over 300 panes of glass in the barracks.” August (mean temperature: 73 F) was the 3rd warmest to date, with 10 rains. The first nine days continued fair, warm, and very humid, most afternoons in the upper 80’s to 90 F. Showers on the 10th finally broke the long three-week hot spell, most subsequent days in the upper 70’s to low 80’s, 14 of the last 21 “cloudy”.
Cool September/October, Mild November/December – This year’s fall-to-winter transition featured the coolest September-October combination to date, succeeded however, by the 2nd mildest November-December tandem. September (mean temperature: 56 F) opened with a few warm days, the 3rd reaching 83 F for month’s highest, but after the first week, cool, cloudy, and rainy weather was the rule, almost every afternoon in the 60’s or lower, nine of the month’s ten rains recorded. The season’s first frost was delayed until the night of the 25th-26th, but it was a hard one: “ice made during the night 1/2 an inch in thickness”. Afternoon temperatures over the 26th-28th were confined to the mid-40’s on each day. October (mean temperature: 45 F) had just four precipitation-days, a 16-day dry spell prevailing over the 2nd-17th. The first half had a mix of mild and crisp days, daily ranges on several in the 50’s for the mornings, the upper 60’s in the afternoons. Several others, though, were only in the 20’s and 30’s for the mornings and the 40’s in the afternoons. On the 10th, Surgeon N. S. Jarvis noted the “atmosphere smokey from prairies on fire”, the first explicit mention of prairie fires in a Fort Snelling weather diary. The month’s maximum, a modest 70 F, came on the 16th, but the 18th was very blustery with high northwest winds, “snow squalls” and slowly falling temperatures to 30 F by evening. Most of the remaining days were cool, afternoons in the 40’s and 50’s, nights freezing or nearly so. Halloween, however, brought mist and fog with 57 F at mid-afternoon. November (mean temperature: 39 F) surpassed last year as the second mildest to date. Like 1833, there were many days of uncharacteristic-ally clear and fine weather. The 1st, a day with “foggy weather” throughout, was an exceptionally mild 66 F at 7AM, this to be the warmest recorded temperature of the whole month. Nearly every one of the next twelve days had afternoons in the 50’s and 60’s as well. Colder weather followed, most afternoons in the 30’s, a few in the mid-20’s, no mornings, however, lower than the mid-teens. In a last taste of Indian Summer, the mercury soared to 64 F on the 20th, but signs of winter were quite evident on the 30th, as a six-inch snowstorm blanketed the Post. During the month, Henry Sibley, future 1st Governor of the State, arrived from Michigan to take a position as manager of the American Fur Company outpost in Mendota [Ford & Johnson, 1961]. December (mean temperature: 20 F) was also mild, dry, and relatively sunny. The first ten days were wintry, though, the mercury dipping to minus 2 on the morning of the 2nd, the Mississippi probably freezing over at this time (no notes of the closing date appeared this Fall). A second snowstorm struck on the 6th (“snow during the night”) and 7th (“snow and high winds during the day”), but after -8 F on the 9th, tying for month’s lowest, a long thawing spell ensued. Nine afternoon 30’s and 40’s occurred over the next twelve days, including 47 F on the 13th. Two “slight” falls of snow and one rain were the only additional precipitation-events before the close, snow cover likely quite light at year-end.