Minnesota (Fort Snelling) weather for the year 1828
A Trend to Drought after Mid-Year –
The relatively mild temperature pattern continued over most of 1828 at Fort Snelling with drought beginning to develop over the second half. Annual mean temperature was 45 F. Winter was very changeable with brief episodes of both severe cold and heavy thaws, the rivers breaking up again in March. Summer was the second warmest in nine years’ history, October to December the mildest such period yet. Conditions from July on also showed a marked drying trend, antecedent of next year’s historic drought and the generally dry conditions that would mark the opening years of the coming decade, the 1830’s.
Changeable Winter Weather – January to early March provided great weather variety, as much as any winter so far in the brief Post history; cold waves, arctic spells, sudden thaws, snows, and even rain made appearances in rapid succession. January (mean temperature: 9 F) started mild, near or slightly above freezing temperatures felt over most of the first week. A sharp cold wave on the 6th, however, dropped the mercury 44 F in just 17 hours to minus 10 F by the following morning. A second even stronger cold wave on the 18th plunged the mercury 55 F in 17 hours to -17 F on the 19th, this and the next day failing to reach zero. The 21st tied for coldest morning of the winter with -22 F registered at 7AM. Snow started to become a frequent occurrence over the last week and into February (mean temperature for the month: 16 F). On 27 January there was “snow during the night”, continuing “during the day” on the 28th. On 1 February, more snow together with sleet and high winds prevailed, followed by another snowstorm accompanied by more high winds over the 3rd and 4th. The mail returned from Prairie Du Chien on the 6th, a day with “rain in the morning”, but a fourth snowstorm moved in on the 8th, a cold spell following in its wake with -17 F recorded on the morning of the 12th. The next week brought a heavy thaw, afternoon readings reaching 50 F on the 16th and 46 F on the 19th, but snow and arctic cold then returned to dominate the rest of the month into early March. February 20-21 had a 16-hour snowstorm, the 25th-26th experienced a 24-hour fall, minus 22 F was felt on Leap Year Day, and March 3rd and 4th had -18 F and -15 F, respectively.
Mild but Variable Spring – Spring, generally mild in mean temperature, had its share of changeable and variable weather as well, in more gradual swings. For the second year in row the Mississippi ice broke up in March but snow was recorded as late as the second week of May. March’s opening frigidity (mean temperature for the month: 32 F) was gone by the end of the first week, dry, mild air replacing it to predominate the weather for the next 2 ½ weeks. Afternoon temperatures climbed to the mid-40’s almost every day, reaching 56 F on the 23rd, and no morning temperatures colder than the mid-teens were felt. The rivers broke up early again, the St. Peter’s clearing on the 22nd, the Mississippi on the 23rd. Unsettled weather moved in for the last week, a three-inch snowstorm occurring, along with a couple of days with thunderstorms and heavy rain. Early April (mean temperature for month: 45 F) was cold and snowy, week one’s temperatures rarely getting out of the 30’s, snow falling on each of the first four days. Mild, clear and dry weather with light southerly winds then followed for the next two weeks, afternoon temperatures generally in the upper 50’s to low 60’s. A brief summery surge came on the 21st with 78 F recorded at 2PM. No precipitation, rain or snow fell for 17 days through the 21st. Weather patterns next switched to cloudy and wet, fifteen days out of the next twenty-four through 15 May having precipitation, some of it heavy. The most unpleasant period was 10-15 May, “heavy rain all day” falling on the 10th, “rain with high wind” also occurring on the 11th. A 15-hour snowstorm prevailed from 6PM of the 12th to 9AM of the 13th [no amounts specified], rain falling as well over “the remainder of the day”. Five hours of “heavy rain” additionally fell on the 15th. Warm and mostly clear weather then returned for most of the remaining days, afternoon temperatures reaching the 70’s regularly with five additional rains. On the 24th, Lt. Colonel Zachary Taylor assumed command of Fort Snelling, his tour of duty to last until 12 July of next year [Hansen, 1958]. Mean temperature for May was 59 F.
Warm Summer, Developing Drought – Summer was warm and dry, the most oppressive hot spell in five years occurring over late July, just three rain-days recorded over this month and August combined. June (mean temperature: 70 F) had relatively seasonable rain frequencies, eleven the count from the register. Afternoon temperatures generally reached the high 70’s to low 80’s, the only exception being an eight-day spell beginning with the 19th with afternoons consistently in the mid-80’s or higher, the hottest 92 F. July (mean temperature: 75 F) tied for warmest calendar month thus far in Snelling history. Temperatures were relatively seasonable over the first half, most afternoons in the low 80’s and cooler, but starting with the 18th, the most oppressive spell since June ’23 set in, six afternoons in a row recorded between 89 F and 93 F. First signs of the incipient drought, just 2 rains and 29 “clear” days were recorded. August (mean temperature: 74 F) was also sunny, warm, and very dry with 26 “clear” days, and one day each of rain and north quarter winds. There were no 90’s, but numerous 7AM temperatures in the 70’s and occasional 80’s. Like last year, the final 12 days were very warm for late summer, most afternoons in the mid-80’s, three as warm as 88 F.
Dry and Mild Fall/Early Winter – The remaining months of 1828 continued mostly mild and dry, October-December showing the most gradual falloff in temperature in ten years’ meteorological history. Precipitation frequencies continued exceptionally low, just two in September and one in October. September (mean temperature: 59 F), a month of pleasant to cool days and mild nights, had only a few 2PM temperatures as high as the mid-70’s, but no 7AM readings lower than 44 F. The month might have been frost-free, but in a bit of observational laxity, no remarks regarding frost events appeared this month, nor for any of the others months this fall. October (mean temperature: 50 F, warmest on record to date) was the province of Indian Summer, with 27 clear days. Morning readings dipped to the high 30’s on the 1st and 2nd, possibly accompanied by the season’s first frost, but a warming trend brought afternoon temperatures at or near 80 F several times over the 7th to 12th, the latest extension of such warmth so late in the Post’s brief history. A two-day cold snap brought 28 F on the morning of the 15th (the season’s first hard freeze), but the rest of the month finished off with mostly south quarter winds, clear skies, and afternoon temperatures in the 50’s and 60’s. November (mean temperature: 35 F) was very cloudy, 23 days of this designation. Afternoon temperatures, generally in the 40’s and 50’s during the first week, fell off to the 30’s and occasional 40’s thereafter, morning temperatures, however, seldom much below freezing and never lower than the high teens. Eight days had snow after the 10th, the amounts unspecified. Unseasonably mild and generally cloudy weather persisted well into December, helping produce the mildest month of its name (mean temperature: 23 F) in ten years. Only two snows fell, the ground likely bare most every day. Afternoons over the first half continued to reach the upper 30’s and 40’s routinely, single figure morning temperatures not occurring until the 17th. A minor cold snap over the 17th to 24th brought some occasional near and slightly below zero temperatures, but clear and balmy weather set in again to close the year, 42 F and 48 F readings recorded during the last week. The Mississippi closed on the 19th.