Minnesota (Fort Snelling) Weather for the year 1829
“The Dry Year” –
Drought predominated 1829’s weather at Fort Snelling, earning the year a place in the early Minnesota history texts along with 1820, 1822, and 1826. According to Neill [1881], winter, spring, and summer were all “very dry … one inch was the average fall of rain or snow for ten months” with “vegetation more backward than it had been for ten years”. May and June combined had only eight rain-days, and a low Mississippi all the way down to at least St. Louis severely hindered the upriver transport of supplies during the summer. Like so many drought years, extremes in temperature, both cold and warm, were experienced. February brought severe cold, late-May and early-June, however, providing unseasonably early intense heat. October and December equaled and exceeded, respectively, the eleven-year marks for high average temperature. November, in contrast, was the coldest month of its name so far in Post history. Annual mean temperature for the year was 44 F.
Mild January but Frigid February – January (mean temperature: 16 F) continued December’s above normal, almost snowless pattern with many thawing and clear days. Just one snow was recorded all month, the ground likely bare much of the time. Following a mix of alternating subzero mornings and thawing afternoons over the first ten days, a new, extended mild regime set in for the 12th to 24th, bringing sunny skies, south to southwesterly winds, and temperatures in the 30’s to low 40’s almost daily. Up to this point, the ’28-’29 Winter was easily the mildest thus far in eleven years of history, but signs of major change appeared over the last several days, as a strong arctic outbreak produced a -18 F reading on the morning of the 29th. Early February decisively erased all balmy winter images with a two-week siege of intense cold. Five of the first 12 mornings were at minus 20 or lower, including -20 F on the 2nd and 5th, -30 F on the 9th, -27 F on the 11th, and -22 F on the 12th. Afternoon temperatures on both the 2nd and 9th only reached minus 8 F. Several snows over the period also resulted in the winter’s first prolonged covering. Average February temperature (2 F) tied December ’22 for second lowest monthly mean in Post history so far, and establishment of a more seasonable temperature pattern wouldn’t really come in earnest until early March.
Exceptionally Dry, Warm Spring – Spring featured another [likely] March breakup of the rivers, intensifying drought, and premature heat. Seasonable in the mean but with large week-to-week variability characterized temperatures during March (mean temperature: 30 F). Precipitation frequency was low, three each of rain and snow. Afternoon readings climbed to the low 50’s on the 9th accompanied by rain, but the next 12 afternoons retreated to the high 20’s and 30’s predominately, with a couple of near zero mornings felt. The last week got much milder, the mercury climbing to 66 F on the 27th, warmest March day in seven years. Continuation of the observational inattention, no notes of the Mississippi breakup appeared this month or next, though there was a high likelihood that the event happened this final week. Thawing temperatures over the interval were felt almost continuously, night and day. April (mean temperature: 47 F) was sunny, dry, and mild, with 24 “clear” days and just four with precipitation. Day-to-day temperatures until the last few showed a very even pattern, ranging mostly from the 30’s in the mornings to the 40’s or 50’s for the afternoons. On the 27th, though, the mercury suddenly leaped to 80 F, the 28th going even higher to 84 F, warmest April temperature yet recorded at the Post, and highest April extreme here for another 25 years. The 29th and 30th also had afternoon temperatures around 80 F. May (mean temperature: 66 F) indicated a full-fledged drought pattern with 27 “clear” days, just four rains, and warm temperatures. Indeed, this would be the warmest May in the local vicinity until 1934, one of the infamous dust-bowl era drought years. Moderately warm weather made up the first half of the month, most afternoons in the 70’s with a few low 80’s. A late frost even set in on the 9th, probably a feedback effect of the dry soil and its greater nighttime radiating properties. The last twelve days, however, turned very hot for the season, nine in the mid-80’s to low 90’s, all but two with predominant south quarter winds.
Droughty Summer – The normal late spring and early summer rains were a virtual failure this year, June (mean temperature: 72 F) having just two falls over the first twenty-three days. Afternoon temperatures continued unseasonably warm through mid-month, frequently climbing to the high 80’s or low 90’s, the 70’s to low 80’s being the rule for the remaining days. This year’s hottest weather came well before the solstice, the 92 F reading on the 15th being the summer’s last ninety-plus temperature. An interesting observational aside on the 17th had Surgeon Robert E. Wood noting a sunrise temperature of 50 F, 11 F cooler than the regularly-scheduled 7AM reading of 61 F some two and a half hours after. While there was no obvious reason for this special recording, the 11 F spread, a typical one for the time of year, exemplified the deficiency of the 7AM/2PM/9PM method in representing overnight minima, 7AM at this season being so far removed from daybreak. July (mean temperature: 72 F) and August (mean temperature: 70 F) were roughly seasonable in mean temperature. A three-day rainy spell finally set in over 25-27 June, but this was followed by another three-week rainless spell, through 16 July. The summer’s only extended wet period came over 17 July to 8 August, ten falls coming in 22 days, but this was succeeded by yet another dry term, a 24-day interval through 2 September with just one rain. It is interesting to speculate how the drought of 1829 would have influenced life in more modern settled times. As it was most intense in late spring to early summer and this is the time most critical for development of commercial crops, it might have been disastrous to the State’s economy. Fortunately, this was still a generation away, the major consequence this summer being the difficulty in moving provisions upriver to the Fort. On July 27, Lt. Reynolds arrived with a keelboat of supplies from St. Louis, half the cargo having to be left at Pine Bend, a few miles below, thanks to a troublesome sandbar. Indicative of likely drought conditions downstream, the trip had “occupied sixty days”, its arrival at Snelling “most opportune, for the garrison was eating its last barrel of flour” [Hansen, 1958].
Oscillating Fall and Early Winter Temperatures – The year’s remaining four months showed large swings in monthly mean temperature departures, October and December matching and exceeding, respectively, high marks for average mildness, November setting a record for coldest. September (mean temperature: 57 F) was relatively cool, most afternoon temperatures confined to the mid-60’s or lower, only two as warm as the mid-70’s. Just two rains fell over the first three weeks, three days in succession recording falls beginning with the 22nd. The first frost occurred on the 14th, not especially early in view of the already dry ground conditions and the resulting greater potential for rapid nocturnal cooling. October, in contrast, was very mild, monthly mean temperature (50 F) tying 1826’s high figure (but only surpassing the modern-day “normal” statistic by 1 F). The mercury hit 80 F on the afternoon of the 2nd, warmer than any day in September, and a spell of 13 cloudy days out of 19 beginning with the 6th produced a large number of unseasonably warm nights in the 50’s. The season’s first hard freeze did not come until the 20th. Three of the month’s modest four rains came over the 6th-10th. November, in contrast, was the coldest thus far in the record (mean temperature: 26 F), thanks in large measure to an unseasonably early six-day cold snap which closed the Mississippi temporarily on the 19th, and produced a minus 7 temperature reading on the morning of the 23rd. Afternoon temperatures reached as high as 50 F only once all month, roughly half the days “cloudy” with five having snow. The first accumulation came on the 9th, the ground likely covered throughout the arctic spell. Continuing the month-to-month thermal anomaly oscillations, December (mean temperature: 24 F) was the mildest on record so far, with much fine and clear weather. Twenty-one clear days were recorded, precipitation consisting of two days each of snow and rain. A mix of brief thaws and subzero cold occurred over the first half, but ten of the last fourteen afternoons were in the 40’s, including 48 F on the 20th and 52 F on the 28th. The 29th was 40 F at 7AM, 46 F at 2PM, and 44 at 9PM, with rain during the day. For the second straight New Year’s Eve, the surrounding landscape was likely devoid of snow.