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Historical Summer Solstice Traumatic Events

Rains and Hail on June 20th:

Thunderstorms rolled across the state on Thursday, June 20th dropping mostly lighter amounts of rainfall, ranging from a quarter to a half inch. However some areas received well over an inch including Redwood Falls, Sleepy Eye, Howard Lake, and Buffalo. Around Owatonna they reported over 2 inches. Reports of widely scattered large hail came from Yellow Medicine, Watonwan, and Martin Counties, and a relatively short-lived tornado touched down in Redwood County near Clements. The rain showers were welcome in some of the drier northwestern areas.

Historical Summer Solstice Traumatic Events:

I thought I would spend this week remembering two famous weather-related historical events that occurred on the Summer Solstice (longest day of the year).

The most recent one was June 21st of 1992 when southern Minnesota recorded its only summer solstice frost in history. Following the eruption of Mount Pinatubo in the Philippines in 1991, much of the northern hemisphere reported one of the coldest summers of the century in 1992. For Minnesota summer of 1992 (June-August) was the 2nd coldest in history (1915 was just 0.3°F colder), and July of 1992 was the coldest in history by far, fully 7.0°F colder than average. The night of June 20-21 1992 brought high pressure, clear skies, and calm winds with very dry dew points ranging from just 25 to 30 degrees F. The Twin Cities hit a record low dew point that night of only 26°F. Much of northern Minnesota saw temperatures fall into the mid to upper 20s F that night, not especially unusual for them. But in southern counties like Fillmore, Goodhue, Wabasha, and Olmsted where the corn crop was only in the 4-8 leaf stage of development, temperatures fell into the low 30sF causing widespread damage. Portions of Wisconsin suffered similar damage as well. Many farmers were aghast that frost damage would occur to their crop on the longest day of the year (roughly 16 hours of day length). Some of the corn was so damaged it was chopped for silage, while other fields were left to recover and regrow. In some fields the tops of plants were clipped off. Where the corn crop recovered there was an estimated 15 to 35 percent yield loss. This remains the one and only time that damaging frost has occurred in major crop regions of Minnesota on the longest day of the year.

The second traumatic weather-related event on the summer solstice in Minnesota is the F-5 tornado (winds over 260 mph) which struck Fergus Falls between 4:30 and 5:00 pm on June 22, 1919. The previous day had brought severe thunderstorms to Otter Tail County as well dumping over 2 inches of rain and causing flash flooding. On the afternoon of June 22nd (the solstice date in 1919) temperatures climbed into the mid to upper 80s F, but the dew points were in the 70s F, producing Heat Index values in the mid 90s F. So the day was quite sticky and tropical. The storm rolled into town from the northwest with a funnel that was 400 yards wide. It stayed on the ground for nearly 20 miles, but went right through the heart of Fergus Falls, destroying 400 buildings, including the hospital and 228 homes. The death toll was 57, with 200 other people injured. This is one of only 8 documented F-5 tornadoes that have passed across Minnesota in the course of our weather history. In addition to the tornado damage, the storm dumped 3.50 inches of rain and large hail. Later that night, after midnight, the same thunderstorm complex passed over the Twin Cities bringing high winds and heavy rains (2.33 inches of rain). The storm flooded cellars, knocked out power, and downed a number of trees, but no tornado.

There is more information about the Fergus Falls tornado of 1919 on the Minnesota DNR State Climatology Office Web Site.

These are undoubtedly two of the worst episodes of damaging weather on the summer solstice and left their mark and traumatic memories with many Minnesota citizens.

Weekly Weather potpourri:

This week the BBC Weather Center features a nice video and explanation of the summer solstice. It might be useful to share with your children who may wonder why it is associated with the longest day of the year.

According to Bob Henson of the Weather Underground much of Western Europe is bracing for an early summer Heat Wave next week. Some areas are expected to see record-breaking high temperatures that may last for several days. Some afternoon high temperatures may reach the mid 90s F. You can read more about this at the Weather Underground web site.

A recent article in the journal ScienceAdvances documents how the Himalayan glaciers of South Asia have seen a doubling in their annual ice loss over the past two decades. These observations are based on aerial photos and satellite images, and conforms with the regional warming temperatures that have been reported.

MPR listener question:

Given the late crop planting this year, I'm wondering whether there will be less "corn sweat" (and soybean sweat) and therefore lower humidity but also higher temperature, at least until the crops develop a full canopy.


Yes, this will probably occur with respect to humidity (dew point), but I am not sure that it will mean higher temperatures. The closest analogy to this unusually late crop planting season is way back in 1979. Back in 1979 crop development was so far behind normal that maximum leaf area, or crop canopy cover was not reached until late July. At maximum canopy cover is when the crop releases the most water vapor through transpiration. In 1979 this was evident when we saw the dew points spike in mid to late August with readings in the 70s F, and producing Heat Index values ranging from 100-105°F. This year crop development is also lagging behind normal by a number of weeks and therefore the maximum leaf area or canopy cover for the state’s corn and soybean crops (about 14 million acres) will occur later this summer. So perhaps we won’t see 70 F dew points until August, may be at State Fair time. Minnesota farmers are certainly hoping for warmer temperatures so that crop growth and development can catch up.

Twin Cities Almanac for June 21st:

The average MSP high temperature for this date is 81 degrees F (plus or minus 8 degrees F standard deviation), while the average low is 61 degrees F (plus or minus 7 degrees F standard deviation).

MSP Local Records for June 21st:

MSP weather records for this date include: highest daily maximum temperature of 95 degrees F in 1910: lowest daily maximum temperature of 59 degrees F in 1906; lowest daily minimum temperature is 39 degrees F in 1992; highest daily minimum temperature of 74 degrees F in 1943; record precipitation of 2.95 inches in 2002; and no snow has fallen on this date.

Average dew point for June 21st is 56 degrees F, with a maximum of 75 degrees F in 1986 and a minimum of 26 degrees F in 1992.

All-time state records for June 21st:

The state record high temperature for this date is 107 degrees F at Canby (Yellow Medicine County) in 1988. The state record low temperature for this date is 20 degrees F at Keliher (Beltrami County) in 2001. State record precipitation for this date is 5.42 inches at Itasca State Park (Clearwater County) in 1957; and no snowfall has occurred on this date.

Past Weather Features:

Clouds and fog persisted on June 21, 1902 keeping temperatures 20 or more degrees colder than normal across the state. Many climate stations reported daytime highs only in the 50s F. The high temperature at Park Rapids was only 56°F.

The massive, intense, and destructive thunderstorms of June 20-21, 1919 brought widespread 2.5 to 5.0 inches of rain to many parts of Minnesota. There were also many reports of large hail and crop damage.

By far the warmest June 21st in state history was in 1988. Over 70 climate stations reported daytime highs of 90°F or greater, while over 20 communities saw temperatures reach or surpass the century mark. At Worthington, the low temperature only dropped to 76°F.


Cooler than normal temperatures will prevail over the weekend along with a chance for showers and thunderstorms each day. Cloudy, with a chance for rain and temperatures in the 40s and 50s F for the runners at Grandma’s Marathon on Saturday morning. Continued chance for showers on Monday, and then a warming trend begins for next week pushing temperatures above normal with a chance for showers and thunderstorms by Wednesday. Some areas may see daytime highs from 85-90 degrees F.

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