Minnesota (Fort Snelling) weather for the year 1836
Backward Early Spring, Cool Late Summer and Fall (graphic)
The new, colder than normal pattern predominated over much of 1836 at Fort Snelling, with a prolonged winter, backward early spring, and unseasonably cool late summer and autumn. Annual mean temperature (42 F) tied 1831’s figure for lowest to date. March was by far the coldest in seventeen years’ history, and the rivers’ breakup was delayed into April for the first time in (likely) ten years. August and October were also the coolest months of their name to date. The first official rain gauge at the Post started service in July, a few heavy storms during this month as well as in August putting it to good use.
A Drawn Out Winter – The ’35-’36 cold season was perhaps the most wearisome in 17 years’ history at Fort Snelling, October/November’s cold and snows being repeated in similarly unseasonable fashion during March/April. The intervening months December to February featured alternating heavy thaws and intense cold. January ’36 (mean temperature: 11 F) opened very mild, thawing temperatures felt on nine of the first eleven days, several with rain and drizzle. A 60-hour thaw (approximately) prevailed over the 5th-7th. A cold wave, however, barreled through on the night of the 11th, temperatures plummeting more than 30 F to minus 3 F by morning. Fifteen of the month’s remaining twenty days had subzero cold at least some of the time, just two reaching as high as 32 F. The winter’s most frigid day came on the 31st: -26 F, -10 F, and -15 F read at the new set of observation times (“A. M.” – sunrise, “P. M.” – 2PM, and “evening” – 9PM). February (mean temperature: 16 F) opened with bitter -24 F, -8 F, and -10 F readings on the 1st. Conditions quickly moderated, though, afternoons from the 4th through mid-month generally reaching the 20’s, only a few nights dropping lower than 10 F. On the 17th, a 4-inch snowstorm blew in, afternoon temperatures holding in the teens, but instead of clearing off colder, a six-day heavy thaw commenced the next day. Afternoon readings on the 19th through the 23rd each climbed into to the mid-40’s to low 50’s. Any thoughts of an impending early breakup were quickly set back, though, as another cold wave late on the 23rd plunged the mercury 38 F in 10 hours to -8 F by the next morning, minus 18 F registered at sunrise of the 27th. Rapid upward advances in temperature and speedy breakups of the rivers (at least from the vantage point of Fort Snelling) had been a routine feature of early spring weather for the past nine years, but this would come to a decisive end in March, thanks to persistent bouts of bitter cold and stormy weather that prevailed through the equinox. Mean temperature (19 F) was at least 5 F colder than any of the previous sixteen Marches back to 1820, and at least 10 F colder than any of the previous ten. Seven of the first eleven mornings dropped to minus 10 or colder, the -16 F reading on the 11th the lowest yet recorded so late in the season here. Stormy weather also accompanied the cold, the 8th having “snow during [the] day & night. High wind”, a four-inch snowstorm blanketing the Post on the 11th, and another “storm of snow & sleet with high wind during the day & night” coming on the 16th. The morning of the 21st dropped to -6 F, another coldest-so-late-in-the-season mark. Spring-like weather finally appeared over the 29th-31st, each afternoon in the 50’s or 60’s, but it was too late – for the first time likely since 1826, the Mississippi and St. Peter’s were still ice-locked at month-end within sight of the Post.
Backward April, A Large Thermal Reversal in May – April, like last year, exhibited unaccustomed fits of cold, snow, and general blusteriness. Monthly mean temperature (43 F) was the lowest since 1826. The first week was pleasant enough, afternoon readings mostly in the 60’s, the Mississippi finally breaking up on the 7th, but conditions then deteriorated again, the next two weeks marked by unseasonable cold, high winds, and storms. Several afternoons barely reached the freezing mark, the unseasonable cold on these made all the more aggravating by “high” northerly winds. The morning of the 10th dipped to 14 F, the month’s lowest temperature, a six-inch snowstorm swept through over the 12th-13th, and on the 20th an additional “severe storm of rain and snow” with “high wind” hit the Post. This being the last of the snow, finally, total accumulation for the ’35-’36 season finished around 50 inches at least, using the fairly complete depth amounts actually cited in the register this winter by Surgeon N. S. Jarvis. The Spring’s first really warm day came on the 25th, observed daily temperature range 54 F to 77 F accompanied by “high” south to southwesterly winds. Similar to 1826, May’s weather was in great contrast with April’s. Monthly mean temperature (64 F) was 21 F warmer, afternoon readings consistently reaching the mid-to-upper 70’s and higher. The 14th hit 87 F for the month’s absolute maximum, “Fair” skies predominated on 28 days, and rain fell on just three.
New Rain Gauge in July, Early Cool Turn in August – Summer, with the exception of a cool August, featured generally seasonable temperatures and occasionally heavy rains, measurements the courtesy of a new rain gauge that started service in July. June (mean temperature: 68 F) opened with seven rains over the first eleven days, but only two additional falls came over the remaining nineteen. The 8th was a chilly 42 F at the new “A. M.” (sunrise) observation time, the following two afternoons confined to the low 60’s, but a four-day spell in the mid-to-upper 80’s followed on the 15th. A number of warm and humid days were felt as well over the last week, temperatures ranging from the mid-60’s in the “A. M.” to the mid-to-upper 80’s in the “P. M”. July (mean temperature: 72 F), pleasant for the most part, brought two welcome rainy spells. The first week was rather eventful, “wild strawberries” reportedly ripe on the 1st, the summer’s two hottest afternoons felt on the 6th and 7th with 93 F and 92 F, respectively. Also on the 7th, the first rain to fall in the new gauge, 0.55 inches, was recorded, another 3 inches to come over the next week. A five-day warm and muggy spell set in over the 19th-23rd, afternoons each in the 88 F to 90 F range, but cooler and wet weather closed the month, 3.73 inches falling over the last eight days. This brought the month’s final total to 7.28 inches, more than double the July normal as we now know it. August (mean temperature: 66 F) surpassed 1832 as the coolest in seventeen years, just three afternoons as warm as the mid-80’s, roughly half in the low 70’s or cooler. Rain fell on seven days to 5.55 inches, about 80% in excess of the modern-day “normal” figure. The first few days had more heavy falls, 1.30 inches coming on the 1st-2nd, the latter having “nine tenths of an inch [falling] in about 30 minutes”. Skies were clear enough the previous night, however, for a “brilliant” Aurora Borealis to be sighted. Another 2.85 inches drenched the Post over the 16th-17th, an early spell of autumn-like coolness following, daily temperature ranges over the 19th-23rd generally in the 40’s for the mornings, the 60’s for the afternoons.
Cool, Dry Autumn/Early Winter – This year’s transition to winter was cool, dry, and evidently quite agreeable to newly arrived Surgeon J. Emerson. Remarks such as “pleasant”, “beautifully mild”, “mild and fine”, “unusually pleasant” and “beautiful” appeared in the register. Steady coolness featured September (mean temperature: 56 F), the first week no warmer than the last. Total precipitation was 4.45 inches on seven days, almost all of this from a several-day wet period around mid-month. Autumnal weather was in control from the start, the season’s first frost coming on the 5th, “high winds for several days and very cool” also noted for the 8th. Starting with the 15th, a slow-moving heavy rain system dropped 3.93 inches over four days, the month’s warmest temperature, a very coolish 74 F, registered on the 17th. “Fair” and crisp weather comprised the remaining days, mornings generally around 40 F, afternoons in the low 60’s. October was also cool, sunny, but much drier, monthly mean temperature (41 F) matching 1833’s low mark. Nineteen days were “fair” in both the “A. M.” and “P. M.”, 0.55 inches’ precipitation recorded on just two. “High Winds” on the night of the 3rd brought “severe frost – destroying all vegetation”. By the following morning, the mercury was 22 F at daybreak. A warming trend then ensued, mid-60’s reached on occasion during the second week, including the monthly maximum 67 F on the 13th. But following this, a premature wintry outbreak spread over the area, afternoon readings over the 16th through 20th only in the mid-to-low 30’s, two inches of snow left on the 18th. “Mild and Fine” weather was back again for most of the last ten, afternoons generally in the 50’s to 60’s, mornings in the 20’s and 30’s. November was similarly sunny, dry, but more seasonable in temperature (monthly mean: 33 F). Eighteen days were “fair”, total measurable precipitation 0.70 inches, all of this rain coming over the 8th and 9th. The mercury reached 56 F on the 1st for the month’s warmest, afternoons over the first three weeks almost exclusively in the 40’s, nights in the 20’s and 30’s. “High” winds on the 22nd introduced a subfreezing spell that held sway through month-end, overnight temperatures, however, never dipping lower than the teens. Lake Pepin froze over on the 24th. Also, “a detachment of recruits – all in good health” arrived on the 26th. December (mean temperature: 17 F) brought mild and virtually snowless weather through mid-month followed by near-record cold. On the 1st, the mercury dipped to 4 F, the Mississippi freezing over next day. But an extended mild pattern quickly followed, most days through mid-month in the 30’s and 40’s, the 7th 49 F and the 8th 48 F. Following 1-2 inches of snow on the 19th-20th, the first measurable precipitation in 39 days, an arctic surge brought -22 F on the morning of the 21st, the mercury staying below zero all day. A four-inch snowstorm accompanied by moderating temperatures came over the 23rd-24th, but on the evening of the latter, an even more intense cold wave drove the mercury down nearly 40 F in 10 hours to minus -28 F by Christmas morning, 1 F shy of 1822’s low mark for December. The year went out mild again, each of the last four afternoons in the 30’s.