SIOUX FALLS, S.D. (KELO) — The rainy weather this week may put some farmers behind schedule in the region but for the week ending Oct. 1 South Dakota farmers were ahead of the five-year average for corn harvest.

Farmers had harvested 16% of the corn crop compared to the 12% five-year average, according to data from the U.S. Department of Agriculture (USDA).

Corn harvest was 2% ahead of the five-year average (21%) in 18 states. In the five-state area around South Dakota, Minnesota is setting the pace at 18% of the corn harvested compared to the five-year average of 8%. Nebraska was next with 22% compared to the average 17%, followed by Iowa at 16% to 12% and North Dakota at 8% compared to 6%.

It’s a slightly different story for soybeans. So far, 23% of the soybeans in 18 states have been harvested. The five-year average is 22%

South Dakota is behind the five-year pace of 26% with 20%. So is North Dakota at 23% compared to 29%.

The soybean harvest is slightly ahead in Nebraska and Minnesota. Nebraska has 29% harvested compared to its five-year average of 27% while Minnesota is at 33% compared to 32%.

Leave dropping is one indicator of soybean maturity or soybeans that are ready to be harvested.

The USDA report said 86% of the soybeans in 18 states are dropping leaves. The report said 82% of the corn in 18 states is mature.

Frost is predicted for parts of South Dakota, Minnesota and Iowa Friday into Saturday. In some places, its predicted for Saturday overnight into Sunday.

A fall frost can affect mature corn and soybeans.

A fall frost can increase the moisture level in both crops.

Iowa State University Extension said in October of 2019 that if a farmer does “harvest the field shortly after a frost, it is recommended to put the soybeans in an aerated bin.”

Temperatures below 32°F can damage soybean leaves, and temperatures below 30°F for an extended time periods can damage the stems, pods and seeds, Iowa State University Extension said in a October 2019 report on a freeze. A killing freeze is considered to be 28°F for soybeans, ISU Extension said.

South Dakota State climatologist  Laura Edwards and Bret Lang, SDSU Natural Resource Management, wrote a Sept. 20, 2022, story for SDSU extension about frost. They said that recorded frost or low temperatures may not always indicate the duration of the frost or low temperature, which is one reason why 28 degrees F or lower is considered a “killing freeze.”