October Weather Update

October Weather Update:

Since last week’s Minnesota WeatherTalk Blog, there have been three significant episodes of Minnesota weather to report on: record heat episode that extended from October 3rd to October 5th; the first rainfall amounts of the month, coming over October 5-6; and then the first widespread frosts of the month coming over October 7 and 8.

The weekend of October 3-5 brought brisk south winds, plenty of sunshine and record heat to many areas of the state. Within the state climate network, over 90 stations reported setting new record daily maximum temperatures on at least one day. Observers in 16 counties reported afternoon high temperatures of 90°F or greater, including 92°F at Redwood Falls and Lamberton. In addition, over the weekend there were at least 60 reports of record-setting warm daily overnight temperatures, including 72°F at MSP on the 4th and 70°F at Cass Lake on the 5th.

Following the weekend heat, showers and thunderstorms moved across the state later on Sunday and Monday bringing widespread rainfalls. Many areas reported a quarter inch to three-quarters of an inch of rain. Some areas reported over an inch of rain, and a few observers reported daily record amounts, including 1.02 inches at Hallock (Kittson County) on October 5th, and 1.40 inches at Preston (Fillmore County) and 1.67 inches at Winona Dam on October 6th. Despite these rainfalls, the area of Moderate Drought in north-central Minnesota expanded over the previous week and now encompasses 12 percent of the state landscape, according to the U.S. Drought Monitor.

Following the rain showers, many observers reported frosts on the mornings of October 7 and October 8. Most of the frosts on the 7th were in northern counties, but the frosts of October 8th were widespread, as over half of the climate stations in the state reported morning low temperatures of 32°F or colder. It even dropped to just 18°F at Brimson (St Louis County) and it was as cold as 29°F as far south as Dodge Center in Dodge County. Many areas in central and northern counties reported lows in the 20s F. Both Hibbing and International Falls reported new record low daily temperatures on October 8th with a reading of 20°F. Several eastern and southern climate stations avoided frost, but reported lows in the mid to upper 30s F. Temperatures rebounded on Thursday, October 9th, with many daytime highs reaching the low to mid 70s F.

Temperatures across Minnesota are expected to remain above normal for the next two weeks, but with more changes for showers and thunderstorms. Temperatures for the first 9 days of October are running about 8°F to 12°F above normal across the state. 

Weekly Weather Potpourri:

According to a research article in Biogeosciences 2024 brought the worst Amazon forest disturbance in over 2 decades. It was due to extensive wildfire -drive degradation. This type of disturbance now largely exceeds human-caused deforestation activities, and is of great concern to long term management of the Amazon forest and preservation of its ecosystems.

According to the NOAA Climate Prediction Center briefing earlier this week, a La Nina Watch remains in place for the equatorial Pacific Ocean. Models suggest a 71 percent chance for the formation of a La Nina episode (cooler than normal sea surface temperatures) over the next two months. Should this occur, it would have implications for the second half of winter in Minnesota and favor cooler than normal conditions in the state.

MPR listener question:

We have heard you speak about climate change in Minnesota and the more recent trend for mild autumn temperatures. Can you tell us specifically what trend the autumn data show? 

Answer:

Sure. I will describe the 15-year temperature trends for September, October, and November in Minnesota.

September has been warmer than normal for 5 consecutive years and 14 of the most recent 15 years on a statewide basis. The warmest in state history was last year (2024).

October has been warmer than normal for 4 consecutive years and in 10 of the last 15 years. The warmest in state history was in 1963.

November has been warmer than normal for 5 consecutive years and 10 of the last 15 years. The warmest November in history was in 2001.

Overall, the three-months we know as autumn (Sep-Nov) have been warmer than normal for 12 of the last 15 years. The warmest autumn season in history was last year (2024).

All of the numbers indicate strong autumn warming trends in Minnesota

Twin Cities Almanac for October 10th:

The average MSP high temperature for this date is 61 degrees F (plus or minus 11 degrees F standard deviation), while the average low is 43 degrees F (plus or minus 9 degrees F standard deviation).

MSP Local Records for October 10th:

MSP records for this date: highest daily maximum temperature of 90 degrees F in 1928; lowest daily maximum temperature of 38 degrees F in 1906; lowest daily minimum temperature of 25 degrees F in 1987; highest daily minimum temperature of 63 degrees F in 1930; and record precipitation of 1.89 inches in 1898. Record snowfall for this date is 2.5 inches in 1977.

Average dew point for October 10th is 41°F; the maximum dew point on this date is 67°F in 1949 and the minimum dew point on this date is 15 degrees F in 2009.

All-time state records for October 10th:

The state record high temperature for this date is 93 degrees F at Tracy (Lyon County) in 1928. The state record low temperature for this date is 6 degrees F at Big Falls (Koochiching County) in 1932. The state record precipitation for this date is 6.13 inches at Vesta (Redwood County) in 1973. A record 10.0 inches of snow fell at Oklee (Red Lake County) on this date in 1970.

Past Weather:

It felt like mid-summer across much of southern Minnesota on October 10 of 1928. Afternoon temperatures hit 90°F in 17 counties. Over 35 climate stations set record daily high temperatures. It was quite a contrast in the north, as Ely reported a high of only 48°F that day.

Record-setting frigid air dominated the state on October 10 of 1932. Many areas reported morning low temperatures in the teens and twenties F. Big Falls, Roseau, Littlefork, and Warroad reported morning temperatures in single digits. The daytime high temperature at Babbitt only reached 36°F.

Residents of western Minnesota thought winter was starting too early on October 10 of 1970. A slow-moving storm brought 6 to 10 inches of snow to many western counties. Fortunately, it was a weekend and the storm did not cause school closures. The snow was short-lived as two days later temperatures climbed into the 50s and 60s F.

Outlook: 

Warmer than normal temperatures over the weekend with a chance for showers later in the day on Sunday. Temperatures will fall back closer to normal for Monday and Tuesday, with a chance again for showers by the middle of next week.