Minnesota (Fort Snelling) weather for the year 1832

Variable Winter Temperatures, Mild Spring & Fall (graphic)

Relative warmth returned again at Fort Snelling for 1832, annual mean temperature (46 F) the third highest in thirteen years. January and February featured great thermal contrasts, spring and fall, however, displaying lengthy periods of unseasonable mildness. Precipitation falls over most of the year continued infrequent.

Great Temperature Contrasts – January, February, and March featured large back-and-forth swings between anomalous cold and mildness, a long thaw occurring in January followed by bitter cold over most of February, this succeeded by the most forward March warmth yet experienced here. Temperatures over the opening days of the new year turned cold again, overnight readings during the first week almost exclusively in the zero to minus 10 range, afternoons in the teens to twenties. On the 7th, though, the most extended January thaw yet to be experienced at Snelling began, afternoon readings over the next sixteen days almost exclusively in the low 30’s to mid-40’s. For roughly 60 straight hours over the 15th to 17th, temperatures were continuously above freezing, the 16th 37 F, 46 F, and 40 F at the prescribed observation times, the 17th 38 F, 38 F, and 34 F accompanied by “rain and snow falling”. Bitter cold, however, struck back with a vengeance on the night of the 23rd-24th, the mercury nosediving 49 F in 17 hours to -21 F by 7AM. The 24th, with readings of -21 F, -14 F, and -26 F, was noted as the “coldest day on record here”, breaking the mark set just last month. While no wind forces were recorded, the northwesterly winds that generated the steep temperature drop must have produced some horrendous windchills. The late cold depressed January’s monthly mean to 16 F, still a high enough figure to tie for second mildest in thirteen years. Not unlike the ’22-’23 winter, February (mean temperature: 6 F) brought resurgent arctic cold, with twenty zero-or-colder temperature days and just two thawing afternoons. Snowcover, which probably came close to disappearing during the January thaw, was restored by six falls, added to the three that had come following the late cold wave. The month’s bitterest temperatures came late, -21 F recorded on the 22nd and -30 F on the 23rd. This latter reading was the latest occurring minus 30 or colder temperature over the entire 1820-1858 Snelling era. The month closed with eleven straight subzero mornings, including –12 F on Leap Year Day. March brought a great thermal reversal, monthly mean temperature (38 F) more than 30 F warmer than February’s, equalling 1822 and 1825’s highest-to-date figures. Four rains were recorded and no snows. Balmy temperatures quickly set in, the 3rd reaching 50 F and the 7th 57 F. A brief but intense arctic blast set upon the area during the night of the 15th-16th, the mercury plunging 50 F in 17 hours to -2 F by the morning of the 16th, just 9 F read at mid-afternoon. But following -1 F next morning, balmy Spring-like temperatures quickly returned, the 19th recording 52 F and the 22nd 56 F. The Mississippi River opposite the Post opened on the latter day. Much warmer weather followed, 67 F recorded on the 23rd and 74 F on the 29th, the latter the highest temperature yet experienced in a March. The 30th brought the first precipitation in 20 days (“thunder & rain”) and a 71 F 2PM temperature.

Warm/Sunny April, Cool/Cloudy May – April and May, not uncharacteristic-ally, were a study in contrasts. The former, like March, was warm, sunny, and dry, monthly mean temperature (54 F) just 1 F lower than April 1825’s record setter. Nineteen “fair” days and five rains were noted. After cooler but still mild weather over the first week, afternoons mostly in the low 50’s, a new warming trend developed, afternoons reaching the 60’s and 70’s consistently over the remaining days. On the 24th, the mercury hit 80 F, warmest of the month. May was considerably cooler than average and much cloudier, monthly mean (55 F) just 1 F higher than April’s. Twenty-two “cloudy” days and seven rains were tallied. Except for the first week in which the 50’s predominated, the majority of the afternoons were in the 60’s and 70’s. On the 10th, the mercury hit 82 F for month’s warmest, just four days later, though, the month’s most dismal day occurred, with rain, northwesterly winds, and a 42 F temperature at 2PM.

Warm June, Cool August – Summer featured generally pleasant and dry weather, early heat coming in June but autumn-like chilliness closing August. June, like so many others of the past 12 years, had a premature warm spell, monthly mean temperature (71 F), several degrees above the modern “normal” figure. Rain fell on eight days. The warmest spell of the whole summer occurred over the 7th to 15th, all but one of the afternoons in the mid-to-upper 80’s. July (mean temperature: 73 F) was roughly seasonable in temperature but quite dry, just four rains recorded. A few afternoons over the first week reached near 90 F, cooler weather, however, setting in over the second, with a few others only in the 70’s. Several additional days around 90 F came after mid-month, the 19th reaching that mark for the warmest temperature of the summer. History was made a couple of hundred miles to the North on the 13th when Henry Schoolcraft discovered the source of the Mississippi River [Ford and Johnson, 1961]. Downstream at Snelling that day, the weather was “fair” with easterly winds and a temperature of 80 F at 2PM. Temperatures cooled significantly in August (mean temperature: 67 F), the coolest summer month here since June ’24. Few afternoons got as warm as 80 F, many in the mid-70’s and lower. Rainfall frequency increased to eight, but no precipitation fell for two weeks over the 13th-26th. The last two days were October-like, the 30th just 52 F, 56 F, and 44 F at the standard observation times, accompanied by rain and northwesterly winds. The 31st was “34 Degrees at 4 O’Clock AM”, easily the lowest reading ever made at Snelling during August. Notes of frost are absent in the diary for that day, though it seems likely that it must have been visible on at least some susceptible terrain in the Post vicinity.

Mild Fall and Early Winter – August’s closing chilliness did not presage a cool autumn or early winter. Indeed, Fall ’32 was the second warmest to date, December commencing the mildest winter until 1877-78. Temperatures over the first days of September (monthly mean temperature: 60 F) quickly recovered from August’s late chill, the 2nd and 3rd each in the mid-70’s in the afternoons, following 60’s temperatures in the mornings. A warming trend near the end of the second week, however, brought even warmer and sultry weather. Four afternoons out of five through the 18th reached the low to mid-80’s, most of the 7AM temperatures observed in the mid-60’s to low 70’s. Following rain on this latter day, much cooler weather set in, the 21st only 50 F at mid-afternoon, the season’s first frost noted next morning. October (mean temperature: 50 F) tied 1828 and 1829 for second warmest to date. The first ten days were relatively cloudy with frequent mild nights in the 50’s, four of the month’s six rains occurring over this interval. Thereafter, uniformly mild, fair, and nearly precipitation-free Indian Summer-like weather ruled, afternoon temperatures typically in the mid-50’s to mid-60’s, morning readings mostly in the 30’s and 40’s, with a few freezing. Only two “cloudy” days were noted over the last twenty-one, the 16th especially warm with a 56 F to 78 F range, reminiscent of the unseasonable warmth a year ago about this time. November was considerably cloudier, but still mild (mean temperature: 33 F). Nineteen “cloudy” days were recorded, more than double October’s total, three snows and one rain falling. The first two days were the warmest, daily ranges on the 1st and 2nd 44 F to 60 F and 50 F to 64 F, respectively. Cooler and duller weather prevailed over the next week, afternoon temperatures declining to the 30’s and 40’s. But several afternoons before the end of the second week reached the 50’s again, accompanied by “fair” skies. A brief but unseasonably early arctic outbreak brought falling temperatures all day of the 17th, the 18th’s temperature range only 8 F to 15 F, the Mississippi closing next day. While this may have been only temporary, no notes of a subsequent reopening/closing appeared during this month or December. A slow warming trend made up the rest of the month, most afternoons in the mid-30’s to 40’s, the 27th reaching 50 F.

Start of an Exceptionally Mild Winter – December (mean temperature: 25 F) surpassed 1829 as the mildest December in 14 years, twenty “cloudy” days tallied in the register. Five days had snow, one recording rain and snow mixed. Afternoon temperatures climbed to the 30’s and 40’s without exception over the first 16 days, only two morning observations colder than 20 F. A four-day spell of northwesterlies brought the month’s only cold snap late in the third week, -11 F read on the 21st, but the mild pattern resumed as the year closed, the 30th 49 F and New Year’s Eve Day 45 F.