Temperatures this October were below average by anywhere from 3 degrees around the MN/SD border to 9 degrees across portions of central SD. A strong low pressure area ushered in multiple days of well-below freezing air in the middle of the month which ended the growing season. Record cold high temperatures were recorded on the 11^th at Watertown (33° vs 35° in 2009), Aberdeen (35° vs 37° in 1959) and Pierre (34° vs 36° in 2009), and again on the 12^th at Sisseton (36° vs 36° in 1959) and Aberdeen (34° vs 35° in 1959).

Precipitation totals finished above average across portions of northeastern and north central SD and west central MN, while central SD was near normal. Snowfall was above average for all but east central SD. Two main storm systems impacted the area. The first, a climatologically early snowstorm from the 10-12^th, was significant across portions of north central South Dakota and especially further north into North Dakota. Record daily snowfalls of anywhere from 0.7” to 4.3” fell at Aberdeen, Watertown, Sisseton, Mobridge, and/or Pierre on the 10^th, 11^th and/or 12^th. More on this event can be found here: https://www.weather.gov/abr/October10-12WinterStorm. The second main system of note this October, a rainstorm on the 20-21^st, dumped generally 1-2” of rain across portions of northeastern and north central SD and west central MN. Daily rainfall records were set on the 20^th at Mobridge (1.08” vs 0.94” in 1963) and on the 21^st at Watertown (0.69” vs 0.52” in 1952), Sisseton (1.88” vs 0.53” in 1931) and Mobridge (0.93” vs 0.32” in 2008).

An interesting note… remember the late spring snows? With just 180 days (between April 12^th and October 10^th), Aberdeen tied their 4^th shortest period on record between the season’s last and first 1” snowfalls (170 days in 1990 and 1970). Similarly, Watertown had 181 days (between April 12^th and October 11^th) which tied their 6^th shortest stretch (164 days in 1979), Pierre had 181 days (between April 11^th and October 10^th) which was their 3^rd shortest stretch (176 days in 1970), Mobridge had 180 days (between April 12^th and October 10th) which was their tied 5^th shortest stretch (170 days in 1990), Wheaton had 182 days (between April 12^th and October 12^th) which was their 3^rd shortest stretch (177 days in 2002), and Timber Lake had just 161 days (between May 1^st and October 10^th) which ranks as their 2^nd shortest stretch (147 days in 1950). This comes on the heels of another short period between between 1” snows at some of these locations in 2018 when mid-April and mid-October snows fell as well.

As noted before, October finished above average for many. Here are updated rankings for total year-to-date precipitation through October 31st: Aberdeen: 27.82” ranks 10^th, Wheaton: 29.84” ranks 7^th, Watertown: 31.75” ranks 2^nd (36.27” in 1977), Timber Lake: 28.44” ranks 2^nd (33.45” in 1915), Pierre: 28.87” ranks 3^rd (31.51” in 1997), Mobridge: 27.51” ranks 1^st (26.73” in 1915), Sisseton: 33.49” ranks 1^st (31.27” in 1901), Kennebec: 33.41” ranks 1^st (29.16” in 1915).

Here are updated rankings of total yearly precipitation through October 31^st (every additional hundredth of precipitation from now through the remaining 61 days of the calendar year will only add to these rankings/records): Aberdeen: 27.82” ranks 16^th, Wheaton: 29.84” ranks 12^th, Timber Lake: 28.44” ranks 5^th (34.10” in 1915), Pierre: 28.87” ranks 3^rd (31.85” in 1997), Watertown: 31.75” ranks 2^nd (40.04” in 1977), Mobridge: 27.51” ranks 1^st (26.86” in 1915), Sisseton: 33.49” ranks 1^st (32.30 in 1993), Kennebec: 33.41” ranks 1^st (30.25” in 1915).

Temperature departures (average of highs and lows) this October, courtesy of the Midwestern Regional Climate Center

Precipitation totals (left) and departures (right) this October, courtesy of the Midwestern Regional Climate Center

Snowfall totals (left) and departures (right) this October, courtesy of the Midwestern Regional Climate Center