October 2021 In Review

October finished above average temperature-wise across the area, by 2 to 6 degrees. The warmest periods were from the 2^nd through the 9^th and from the 16^th through the 19^th when high temperatures rose into the 70s and 80s. Overall on the year, Aberdeen has now recorded 116 days with a high temperature of at least 80 degrees in 2021, which ranks as the 3^rd most on record (118 days in 1936 and 1900). Similarly, Timber Lake has had 106 days which ties for 4^th most, Sisseton 103 days which ranks 6^th, and Mobridge 106 days which ranks 9^th. Cooler temperatures arrived for the second half of the month: the growing season ended, as hard freezes occurred, and albeit light, the first snow of the season took place at some locations on the 20^th.

A shift to a wetter pattern, particularly across northeastern South Dakota, continued into October when several systems impacted the area. Wheaton and Mobridge recorded their 8^th wettest October on record, Timber Lake 7^th, Sisseton and Aberdeen 6^th, and Watertown 2^nd with 7.63” of rainfall (8.10” in 1971). Daily record rainfall occurred on the 9^th, 13^th, 20^th and 27^th at Aberdeen, Watertown, Sisseton and/or Mobridge. Unfortunately, late-season severe weather including several tornadoes accompanied these systems on the 9^th and 13^th across northeastern South Dakota and west central Minnesota. Prior to 2021, there had been just 18 total October tornadoes confirmed in the state of South Dakota, and 29 in Minnesota. 10 additional tornadoes were confirmed in South Dakota and 14 in Minnesota this October alone. Find much more information here: https://www.weather.gov/abr/October2021SevereWeather. Drought conditions continued to improve in response, going from D3/Severe Drought across portions of north central SD and D2/Severe Drought across the majority of Central SD on September 28^th, to just portions of D2/Severe Drought across Central SD by October 26^th.

*October 2021*
Temperature Data	Aberdeen	Sisseton	Wheaton	Watertown
Warmest Temperature / Date	88 / 4^th	84 / 4, 5^th	82 / 5^th	81 / 4, 8^th
Coldest Temperature / Date	25 / 29th	23 / 23^rd	28 / 23^rd	28 / 16, 31^st
Average High / Departure from Normal	63.6 / +4.3	62.8 / +4.8	64.4 / +3.7	61.0 / +4.8
Average Low / Departure from Normal	39.9 / +6.6	41.7 / +6.2	42.1 / +5.4	40.2 / +5.0
Monthly Average / Departure from Normal	51.8 / +5.5	52.3 / +5.5	51.7 / +4.5	50.6 / +4.9
Precipitation Data
Monthly Precipitation / Departure from Normal	4.39 / +2.25	4.97 / +2.64	4.27 / +2.27	7.63 / +5.68
Most Precipitation in 24 hours / Date	1.18 / 9th	1.35 / 13^th	1.35 / 10^th	2.27 / 9-10^th
Monthly Snowfall / Departure from Normal	T / -1.3	0.0 / -1.0	0.0 / -1.0	T / -1.4
Most Snow in 24 hours / Date	T / 20^th	0	0	T / 24th

Temperature Data	Pierre	Kennebec	Mobridge	Timber Lake
Warmest Temperature / Date	86 / 4, 5^th	83 / 4, 5^th	87 / 5^th	88 / 4, 5^th
Coldest Temperature / Date	25 / 31^st	25 / 15^th	22 / 31^st	19 / 21^st
Average High / Departure from Normal	63.8 / +3.1	64.6 / +0.8	63.5 / +3.1	61.8 / +3.1
Average Low / Departure from Normal	40.7 / +4.5	39.6 / +4.0	41.4 / +4.9	39.6 / +5.0
Monthly Average / Departure from Normal	52.2 / +3.7	52.1 / +2.4	52.4 / +4.0	50.7 / +4.0
Precipitation Data
Monthly Precipitation / Departure from Normal	2.09 / +0.40	3.07 / +1.44	3.43 / +1.62	3.45 / +1.66
Most Precipitation in 24 hours / Date	0.70 / 9^th	1.23 / 20^th	1.52 / 12-13^th	1.89 / 13^th
Monthly Snowfall / Departure from Normal	0.0 / -1.3	0 / -1.6	T / -1.7	0.2 / -2.1
Most Snow in 24 hours / Date	0	0	T / 20th	0.2 / 20th

October 2021 temperature departure from normal, from the Midwestern Regional Climate Center

Daily high temperatures (values) and departures from normal (rectangle shading) at Aberdeen, Watertown and Pierre

October 2021 precipitation totals, from the Midwestern Regional Climate Center

October 2021 precipitation departure from normal, from the Midwestern Regional Climate Center

US Drought Monitor comparison between October 26th, left, and September 28th, right.

Precipitation accumulation graph from January 1st through November 1st, at Aberdeen, Watertown, Sisseton, Pierre and Mobridge (from top to bottom, in that order). At Aberdeen and Mobridge, more rain has fallen from Aug 18th - Nov 1st than from Jan 1st - Aug 18th (10.18" vs 8.04" at Aberdeen and 8.67" vs 6.16" at Mobridge). Also, notice that rainfall deficits have turned to surpluses at Watertown and Sisseton.