National Weather Service United States Department of Commerce

1890 - 1908
Weather observations begin in Sioux Falls, taken by volunteer observers. Though primitive by today's standards, the observations are the building blocks of the Sioux Falls climatic history.

1908 - 1945
J.H. Bechtold, a Sioux Falls businessman, took climatic weather observations from his home at 610 N. Summit. His weather records are important in maintaining continuous climatic weather information while the Weather Bureau Office is closed during World War II.

1936 Summer
The summer heat wave of 1936 is the hottest on record with 21 days of 100 degrees or higher. This included 9 days in a row of 100 degrees or higher from July 9-17. The highest temperature on record was 110 degrees on July 17, 1936 and again on June 21, 1988, in another notoriously hot and dry summer.

1941, November 1
Weather Bureau Office first starts taking observations (after office opens in September). Location is the Old Administration Building at the Sioux Falls airport. Office operations including observations are suspended on Nov. 30, 1942 due to World War II, and J.H. Bechtold continues official observations.

World War II caused the Weather Bureau Office to close in August 1942 for the duration of the war.

1945, December 31
Weather Bureau in Sioux Falls opens. Because of the loss of men during World War II, the first employees are women. 

1947, September 24
Weather Bureau moves to the 1st floor of the New Administration/ Hangar Building, 500 feet southwest of Old Building.  The new lease costs the government $1 a year.

1951 and 1952, April
In April of both years, the Big Sioux River floods the airport, causing the Weather Bureau to temporarily move its operations to the Coliseum downtown. In 1952 plans were started to build the diversion channel and levees.

The Weather Bureau disseminates its first Local Forecast to the public.

1956, April 18
The first radar, a WSR-1, is put into service. The radar is out of a vintage World War II aircraft.

1957, June 16-17
Biggest rainfall flood in Sioux Falls history (record stage for Skunk Creek)

Diversion channel and levees in Sioux Falls are completed.

1962, February 17-18
Biggest snowstorm in Sioux Falls history with 26.0 inches snowfall in 24 hours, contributing to the total of 48.4 inches for February, for the snowiest month on record.

1969, April
Biggest snowmelt flood (and all-time on Big Sioux River) in Sioux Falls history, followed the snowiest winter season on record with 94.7 inches total snowfall.

The Weather Bureau is reorganized under the National Oceanic and Atmospheric Administration (NOAA) and becomes the National Weather Service.

1971, January 12
Office moves to 1 Weather Lane, 1 mile north of previous site. Office becomes Weather Service Forecast Office in 1972 with both public and aviation forecast responsibility for the state of South Dakota.

1972, June 12
Sanford ( Sandy) Miller assumes position of WSFO Meteorologist In Charge (MIC). Sandy holds the position for 5 years until his retirement in 1977.

1975, January 10-11
Worst blizzard on record with 70 mph winds, -70 degree wind chills, 7 inches snowfall, and visibilities below a quarter mile for 24 hours.

1975, August 1
One of the heaviest official rain events for Sioux Falls with 4.59 inches measured at the airport.

1976, April 21
New weather radar, a WSR-74C, watches over larger area than before.

Driest year of the century with only 11.42 inches precipitation, and one of the worst droughts on record, especially in the summer.

1978, January 15
Rollin Mannie takes over as WSFO Sioux Falls MIC and holds the position for 12 years, until his retirement in 1990.

NOAA Weather Radio is first installed for the tri-state area around Sioux Falls.

1980, July 29
AFOS, a computer/communication system, is placed in service, and through 1981 it gradually replaced all teletypes and fax machines.

1982, July 6
Worst thunderstorm downburst hits Sioux Falls in the early afternoon with up to 125 mph wind gusts causing damage and uprooting numerous large trees, mainly in south central and northeast sections of the city.

1983 December
One of the worst cold waves ever, with a record 8 days in a row from Dec. 17-24 when the temperature stayed below zero and numerous daily record lows were set. Blizzard conditions existed on Dec. 23-24 with near zero visibility in blowing snow and wind chills down to 80 below zero.

1986 April 13-14
A spring blizzard west of Sioux Falls resulted in the worst livestock losses in state history.

1989, July 17
A small tornado hits western Sioux Falls doing extensive damage to 6 houses.

1990, December 30
Greg Harmon becomes the third Meteorologist in Charge (MIC) of WSFO Sioux Falls and leads the office modernization to Weather Forecast Office status throughout the 1990s and early 2000s. Early in his NWS career, Mr. Harmon spent time at WSFO Sioux Falls as a meteorologist intern from January 1975 until March 1978, returning as MIC some 12 years later. Mr. Harmon still holds the position of MIC.

1991, October 31
One of the earliest heavy snowstorms was the “Halloween” blizzard of Oct. 31 – Nov 1 when a foot of snow was followed by blizzard conditions.

1992, June 16
F-5 tornado hits Chandler, MN, 40 miles northeast of Sioux Falls, for the only F-5 tornado in the U.S.A. in 1992.

1993, May 22
Worst flash flood hits southwest Sioux Falls due to stationary thunderstorm dumping 5 to 7.5 inches of rain within 3 hours.

Most tornadoes ever in one year in South Dakota, 85, all from May through August, compared to a yearly average of 26 in the state.

1993, September 14
The National Weather Service moves into its new facility at 26 Weather Lane. The new building will host a variety of advanced technological systems, including the new doppler radar system, WSR-88D.

1993, December 3
The WSR-88D radar is turned on. The radar is commissioned on October 18, 1995 making it the official operational radar for WSFO Sioux Falls.

1994, April 28
One of the latest heavy snows on record with around 11 inches in the Sioux Falls area.

1995, October 18
WSR-88D commissioned. Old WSR-74C radar decommissioned in fall of 1996.

1996, March 11
The National Weather Service Sioux Falls Homepage is placed onto the Internet's World Wide Web.

1996, April 1
ASOS (automated surface observation system) is commissioned at Sioux Falls. (ASOS is augmented for weather and climatic information by human observers at Sioux Falls.)

1996, April 1
The Weather Service Forecast Office (WSFO) at Sioux Falls becomes the Weather Forecast Office (WFO) for both forecast and warning responsibility in southeast South Dakota, bigger portions of northwest Iowa and southwest Minnesota, and far northeast Nebraska.

1996, November 15-16
Worst icestorm of the century hits the tri-state area around Sioux Falls with 2-3 inches of precipitation in the form of freezing rain, sleet, and some snow.

1998, May 30
F-4 tornado hits Spencer South Dakota, about 40 miles west of Sioux Falls. Most of the town's 190 buildings were severely damaged or destroyed.

1998, October 1
NOAA Weather Radio Console Replacement System (automated voice system) is installed, and is commissioned on Mar. 6, 2000.

1999, March 22
AWIPS (Advanced Weather Interactive Processing System) is installed and begins to replace the AFOS computer system. AWIPS is commissioned Apr. 4, 2000.

2001, December 4
The digital forecast era begins with the first products prepared by Meteorologists using the Interactive Forecast Preparation System or IFPS. Graphical forecasts of various weather elements are prepared on this system and sent out to various media including numerous internet users. All text forecast products were issued using IFPS on February 4, 2002.

2003, June 24
One the largest tornado outbreaks in our Nation’s history hits southeast South Dakota. Over an 8 hour period, 67 confirmed tornadoes touched down across the WFO Sioux Falls County Warning Area. This was a record-breaking event for South Dakota, and the 67 tornadoes also tied a national record dating back to 1967 for the greatest number of tornadoes in a state within a 24 hour period. One tornado was rated F4 packing winds in excess of 200 mph, and 8 other tornadoes were rated F2 or F3.

2004, May 29 and June 16
Two major rain events cause flash flooding of many homes and roads in Sioux Falls. At the airport, 4.22 inches was recorded on May 29, and 3.58 inches on June 16. However, there were other reports up to 6 inches around Sioux Falls between 6 pm and midnight on May 29, and up to 7.50 inches in southwest Sioux Falls between 4 am and 8 am on June 16. With the event on June 16, Sioux Falls ended up with the wettest 31 day or monthly period on record, with a total of 12.74 inches precipitation.

2005, November 27-29
One of the worst winter storms in South Dakota history occurs in the eastern half of South Dakota, especially the James Valley, where a severe icestorm was followed by a heavy snowstorm/blizzard. 1 to 2 inches of freezing rain caused extensive damage to power lines and poles, knocking out power for days in many areas. Snowfall varying from 4 to 15 inches combined with wind gusts over 50 mph caused snow drifts as high as 6 to 8 feet in a few areas. A man died of exposure in the blizzard north of Harrison in Douglas County, or about 90 miles west of Sioux Falls.