Summary

During June 2021, temperatures were well above normal across the Upper Mississippi River Valley. Temperatures were 5 to 8°F warmer-than-normal.  Monthly average temperatures ranged from 66.1°F at Medford, WI to 76.6°F at La Crosse Regional Airport.  La Crosse, WI had their hottest June.  The previous record was 76.5°F in 1933.  Many other locations in the Upper Mississippi River Valley had one of their 5 warmest Junes.

The hottest daily temperature was 100°F on June 6 and June 11 in Theilman, MN (Wabasha County).  These were the first 100°F days in the Upper Mississippi River since May 15, 2013 (Austin, MN).

Like May, June 2021 precipitation was highly variable across the Upper Mississippi River Valley.  The driest areas continued to be found in southeast Minnesota, northeast Iowa, and southwest Wisconsin. Precipitation totals were up to 2” wetter-than-normal along and north of Interstate 90 in Wisconsin and up to 3” drier-than-normal across northeast Iowa and southwest Wisconsin.  Precipitation totals ranged from 1.30” two miles northeast of Rochester Airport (Olmsted County)  to 12.96” near Harpers Ferry, IA (Allamakee County).  A majority of this rain fell during the last half of the month.

Below are some of the climate sites which saw one of their driest Junes. 

• Guttenberg Lock & Dam 10, IA received 1.39" of rain which was 4.31" drier than the 1991-2020 normal of 5.70". This made it their 5th driest June and the driest since 2012 (0.95" - 3rd driest).  Their driest June occurred in 1988 (0.45”).
• Rochester International Airport, MN received 1.46" of rain which was 3.89" drier than the 1991-2020 normal of 5.35". This made it their 7th driest June and the driest since 1985 (0.94" - 2nd driest). Their driest June occurred in 1910 (trace).

On June 26-27, a low-pressure area produced heavy rain as it moved northeast through parts of northeast Iowa and southwest Wisconsin.  The heaviest rain across southeast Allamakee County (IA) and the northern two-thirds of Crawford County (WI).  These areas received rain totals anywhere from 6 to 9.50”.  The highest totals were just northeast of Gays Mills, WI (8.47”) and about 3 miles east of Harpers Ferry, IA (9.50”).  Both locations are in Crawford County.  This rain caused flash flooding and mudslides during the early morning hours of June 26.  In addition, there was minor flooding along the Kickapoo River at Gays Mills and Steuben.

Flood Conditions

On June 26-27, there was minor flooding along the lower portion of the Kickapoo River.  Gays Mills crested at 13 feet on the morning of June 26.  The flood stage is 13 feet.  Steuben crested at 12.73 feet on the morning of June 27.  The flood stage is 12 feet.   

River Conditions

For much of June 2021, the USGS river flows were below- to near-normal.  The only river flooding was along the rivers and streams in southeast Allamakee (IA) and Crawford (WI) counties on June 26-27.  This included minor flooding along the lower portion of the Kickapoo River (Gays Mills & Steuben) in southern Crawford County. 

Drought

June 2021 began with much of the Hydrologic Service Area (HSA) either abnormally dry (D0) or in moderate drought (D1).  The combination of near to record heat during the first half of the month and dryness which in some areas began in late 2020 caused severe (D2) drought to develop along and south of Interstate 90 by mid-month.  For many of these locations, this was the first time that there was severe drought since the 2012-13 drought (mid-July 2012 to mid-April 2013).  The rains returned in mid- to late June.  This caused some improvement in the drought for west-central Wisconsin and parts of southeast Minnesota and southwest Wisconsin.  By the end of June, 27.43% of the area was abnormally dry (D0), 54.18% was in moderate drought (D1), and 12.31% was in severe drought (D2).