South Dakota Weather History and Trivia

October 1 -

The average date of the first freeze in Sioux Falls is October 1st. The earliest first freeze on record occurred on September 3rd, 1974 when the temperature dipped to 31 degrees. The latest first freeze on record occurred on October 28th, 1963.

October 2 -

Methane (also known as swamp gas), along with carbon monoxide, is a major greenhouse gas. Because of population growth and changes in the planet's land use patterns, by the year 2000 atmospheric methane is expected to be six times as high as it was in the year 1800. Although a greenhouse gas that could, in theory, lead to an increase in global temperatures the higher methane levels' actual effect on the earth's climate remains under debate.

October 3 -

One of the very first computers dedicated to atmospheric science performed about 1000 additions a second. Today's larger, more powerful machines clip out over a billion additions per second and that's not nearly enough to approach duplicating the incredible complexity of the atmosphere or satisfy atmospheric researchers.

October 4 -

Something that is an important consideration for meteorologists across much of the central plains is something called the upslope effect. The upslope effect is caused by the gentle rise in elevations across the central plains from the Mississippi River to the Rocky Mountains. As air flows up this gentle rise the lifting of the air leads to cooling. This cooling can contribute to extensive cloud cover, fog, and precipitation, especially in the winter months.

A more pronounced upslope effect can occur along the Rockies and the Black Hills of South Dakota. If winds force air directly into these mountains or hills the air will be lifted along the earthen boundaries. This dramatic lifting will often lead to the development of thunderstorms in the summer, or significant snows in the winter, along the mountains and hills that the surrounding lower elevations do not receive.

October 5 -

October 5th, 1982 strong thunderstorms developed across central South Dakota and raced into portions of southwest Minnesota. The storms were prolific lightning producers in South Dakota setting several structures on fire. An electrical substation was damaged near Salem, an elementary school was set ablaze in Aberdeen, and several homes in Sioux Falls were struck as well. One home in Sioux Falls had a new hole knocked in a wall by a lightning strike.

Numerous fires were also started in southern Minnesota by the same line of storms. Strong thunderstorm winds leveled several buildings, damaged a house, and moved a hog shed off its foundation on three separate farms near Worthington. The winds also turned over railroad cars near Pipestone. Worthington narrowly escaped damage as a small tornado touched down two miles southwest of town and moved southeast. Fortunately, the tornado's damage was confined to trees and crops.

October 5 -

The hottest temperature ever recorded in the month of October occurred on October 5th, 1963. The mercury climbed to a steamy 94 degrees that day.

October 6 -

If you like lots of the sun then, not surprisingly, the best place in the United States for you is in the desert southwest. The sunniest city in the U.S. is Yuma, Arizona which sees 90% of the yearly possible sunshine. Second on the list is Las Vegas, Nevada which receives around 85% of the possible sunshine. Las Vegas also holds the distinction of being the least humid city in the country with an annual average relative humidity of just 30.5%.

In contrast, most of the northern plains see around 50 to 60% of the possible yearly sunshine.

October 7 -

On October 7th through the 9th, 1970 a record breaking early season snow storm rocked parts of southern South Dakota. Snowfall of 5 to 9 inches was common across the southwest and south central on the 7th. Late on October 8th and into the 9th of 1970 the southeast portion of the state was hit. Vermillion received 6 inches of snow on the 9th and that is the largest amount ever recorded there for so early in the season. The 5 inches that fell in Sioux Falls is the earliest significant snow on record for the area.

The heavy snows also affected portions of western Iowa and western Minnesota. Amounts of up to 7 inches were recorded in northwest Iowa. The heavy, wet snow snapped many tree branches and downed power lines. Sioux city recorded their heaviest snow for so early in the season. The snow was very wet and heavy, but melted quickly over the next several days.

October 8 -

October 8th and 9th, 1982 a record-breaking snowstorm for so early in the Fall paralyzed the northern Black Hills with three to six feet of heavy, wet snow and winds of 40 to 70 miles an hour. Some snowfall amounts included 41 inches at Galena, 36 inches at Lead, and 23 inches at Deadwood. Five to six feet of snow was common in the higher elevations.

The heavy wet snow caused numerous problems. The roof of a clothing store in Lead collapsed under the weight of the snow and several other businesses were damaged. The roofs of at least three trailer homes also collapsed. The combination of strong winds and heavy snow broke tree branches (causing extensive timber damage), power lines and telephone poles. Damage as done to 40 miles of power lines, including 30 broken power poles. Some residents were without power for five days. The city of Deadwood was without electricity and fresh water for at least three days.

October 9 -

October 9th, 1973 heavy rains and hail pounded extreme eastern South Dakota during the late evening hours. 3.79 inches of rain fell in a 2 hour period at the Sioux Falls airport setting a new rainfall intensity record for a two hour period in Sioux Falls. The 4.54 inches that fell that day is the second highest amount on record for a 24 hour period in Sioux Falls.

The thunderstorms then raced into western Minnesota and northwest Iowa. Strong thunderstorm winds downed trees, power lines and several farm buildings across Plymouth, Sioux, O'Brien, and Osceola counties. Two small tornadoes also developed across northwest Iowa that evening. The first was near Hinton (in Plymouth county) and the second was near Sheldon (in O'Brien county). Fortunately, neither tornado did much damage.

October 10 -

October 8th through October 10th, 1982 record amounts of snow piled up in the northern Black Hills. Not only was the storm a record breaker because it came so early in the season, it was a record snowfall producer for anytime of year.

Amounts of three to six feet were common across the northern hills. On October 9th, 1982 thirty-two inches of snow buried Lead. The thirty-two inches that day is the most on record for a 24 hour period in South Dakota. Lead's three day storm total of 55.3 inches is the largest single storm total on record in South Dakota. To put the 55.3 inch storm total in perspective the tri-state area around Sioux Falls averages about 40 inches of snow in an entire winter.

October 11 -

What city in the United States has the most days with precipitation? Well, not by coincidence Hilo, Hawaii, which is the wettest city in the country with an annual average precipitation of 128.00 inches, also has the most rainy days at 277. Number 2 on the list is Quillayute (pronounced key-a-ute), WA with 210 days. By contrast, Sioux Falls averages 97 days a year with precipitation.

October 12 -

Living in the mid-latitudes as we do allows us to experience a wide range of weather phenomena and temperature extremes. The range of recorded temperature extremes in the United States is 214 degrees Fahrenheit. The hottest temperature on record in the U.S. is 134 degrees and the coldest is -80 degrees. The recorded temperature range for the entire planet is an amazing 263 degrees. With the hottest temperature on record being 136 degrees and the coldest is a bone chilling -127 degrees.

Sioux Falls has a range of 152 degrees between its highest and lowest temperatures. With 110 degrees being the hottest and -42 degrees the coldest. In contrast some tropical islands have never seen their temperature vary by more than 30 or 40 degrees.

October 13 -

Late on October 13th and early on the 14th of 1966 a late season round of thunderstorms across south central and southeast South Dakota was accompanied by hail and strong winds. The hail and winds caused extensive damage to the soybean crop that year. The strong winds downed numerous utility lines, as well as some farm buildings. In Lake Andes (in Charles Mix county), lightning struck a church and the building was destroyed in the ensuing fire.

October 14 -

Approximately twelve percent of our nation's electricity comes from renewable resources: hydroelectric, biomass, municipal waste, wind, solar, and geothermal. Hydropower is by far the largest contributor. However, most of the country's major rivers are already being utilized for hydropower, therefore, additional hydroelectric power resources are minimal. Use of wind and solar power has quite a bit of potential as an increased energy source.

October 15 -

Good news for folks looking for a cleaner more environmentally safe energy source. Between 1980 and 1992 the cost of solar-generated electricity dropped around 1,000 percent. One industry group predicts that solar power could be cost competitive with conventional electrical utilities by the turn of the century. Of course, solar power also has the tremendous advantage of being a renewable resource.

October 16 -

A squall line packing damaging winds developed across portions of central south Dakota and raced into Minnesota on the afternoon and evening of October 16th, 1980. The line of thunderstorms developed around 2 pm CDT and moved east and northeast at over 50 miles an hour. A large portion of southeast South Dakota was belted with winds of 50 to 70 miles an hour. Yankton reported winds of 60 to 70 miles an hour while Sioux Falls was hit with a 62 mile an hour gust. Considerable damage was done in southeast South Dakota to trees, farm structures, and small buildings. Damage estimates were 100 to 200 thousand dollars.

By late afternoon the thunderstorms were roaring through southwest Minnesota. Numerous outbuildings and many trees were downed or damaged. In Redwood county two combines and a 24 foot travel trailer were tipped over and damaged.

October 17 -

Wind power has the potential to become a fairly significant energy source across portions of the United States. The possibility of wind generating electricity was brought about with the combination of advancing technology and the old idea of windmills. Apparently, windmills were first used extensively in the Middle East all the way back in the 11th century. Around 200 years later they became established in Europe. In the 1400's the Dutch were using wind power to drain swamps and marshes and before the start of this century, the Danes were using wind to generate some 40 megawatts of electrical power. In the future in this country wind power may generate up 10 percent of the electricity in some areas.

October 18 -

Annual weather related losses in the United States are estimated to be as high as $34.5 billion dollars. New technologies are helping to prevent losses that could be significantly higher than this. Weather satellites save the country money. According to the National Oceanic and Atmospheric Administration (NOAA), the use of information supplied by weather satellites saves key industries such as agriculture, construction, shipping, fishing, utilities, and aviation more than $5 billion dollars a year.

October 19 -

On October 19th, 1982 an early Fall snowstorm dropped 3 to 12 inches of wet snow over the southeast portions of South Dakota and up to 8 inches in southwest Minnesota and northwest Iowa. Numerous trees still laden with foliage were downed across the area. Power outages were also extensive from Vermillion to Mitchell. The snow was convective in nature as lightning flashed and thunder rumbled in some areas. Winds up to 40 miles an hour in concert with the heavy snow proved too much for some structures. Radio and TV transmitters were knocked down in Sioux Falls and in Vermillion the weight of the snow collapsed the fiber glass roof panel on the covered stadium at the University of South Dakota.

October 20 -

What nation has the worst weather on earth? If you consider the range of possibilities (heat, cold, floods, drought, tornadoes, tropical storms, etc.) the United States happens to come up number one. We receive this dubious distinction through a combination of factors. Some of the important influences include being on a large land mass in the mid-latitudes which allows for a greater range of temperatures in the interior, as the land heats up and cools down much more quickly than areas near water. This leads to clashes of vastly different air masses as cold, dry air moves into the country from the north and warm, moist air settles in from the south. Also, the Gulf of Mexico is a significant and, often, easily accessible moisture source that fuels inclement weather across the eastern 2/3rds of the country. But, these are only a couple of the factors that contribute to our wild weather in the U.S..

October 21 -

Have you ever heard the weather saying "When the wind is out of the east, 'tis good for neither man nor beast?"

Well, there is some truth to the old saying. Typically, if one is experiencing a northeast or east wind it means that an area of low pressure...which often produces inclement nearby.

October 22 -

Trees happen to be one of nature's best fighters of air pollution. It os reported that one acre of trees can filter a massive 13 tons of dust and gaseous pollutants from the air per year.

October 23 -

On a nice clear day you may have heard someone say they could see "forever". In actuality, the limit of visibility in a perfectly clear atmosphere, meaning a minimum of dirt or pollution, is around 200 miles.

October 24 -

Some old folklore goes "If the rooster crows at night, he's trying to say rain's in sight."

There is actually some merit to the old saying. Basically, a rooster's feathers act as insulation, so the changes in air pressure, temperature, and humidity that precede a inclement weather may make a rooster uncomfortable and cause him to crow.

October 25 -

In every month of the year, the warmest temperature on record in the U.S. is 100 degrees or higher. In nine out of the 12 months the record low in the U.S. is below zero. The record U.S. record low in June is +2, in July it's +10, and in August it's +5 degrees.

October 26 -

For all you fishing fans at there here's a little weather folklore for you. There is some truth to the saying "when fish break water and bite eagerly, expect rain." The connection with the weather is this: when the barometric pressure starts to fall (this often precedes precipitation), gas bubbles in the water clinging to decaying matter expand and cause the matter to rise to the surface. This moves the whole feeding chain to the water's surface.

October 27 -

The driest month on record for the state of South Dakota occurred in October 1952. For that month the average precipitation at recording sites across South Dakota was a paltry .02 of an inch.

October 28 -

The latest first freeze on record in Sioux Falls occurred on October 28th, 1963. The average date for first freeze is on October 1st. In 1963 it came a full four weeks later when the temperature fell to 23 degrees.

October 29 -

October 29th, 1925 is the coldest day on record in the month of October in Sioux Falls. The temperature dipped to a cold 5 degrees below zero that morning and still stands as the earliest day in the year that Sioux Falls has reached 5 below zero.

October 30 -

A narrow band of heavy, wet snow developed late on October 30th, 1979. The band of snow stretched across central and south central sections of South Dakota and produced amounts of three to six inches late on the 30th and early on October 31st, 1979. Winds of 30 to 50 miles an hour pasted the snow to power poles and the tremendous weight snapped some 600 poles. The damage exceeded $400,000 dollars.

October 31 -

A strong winter storm belted sections of the Northern Plains October 31st through November 2nd, 1991. Sioux Falls accumulated an impressive 11.2 inches in a 24 hour period from October 31st to November 1st. That is the earliest heavy snowfall (that's a snowfall of 6 inches or more) on record for Sioux Falls. The storm also made it the snowiest October on record in the city with 10.0 inches. is the U.S. government's official web portal to all federal, state and local government web resources and services.