WASHINGTON — The U.S. Department of Agriculture’s most recent Crop Progress report released June 23 showed modest declines from a week earlier in condition ratings of U.S. corn and soybean crops, although ratings were better than a year earlier.

Excessive rainfall in the northern Midwest was being blamed for the small declines in the corn and soybean crops’ good to excellent ratings. In addition to slowing wheat harvest progress, precipitation well in excess of normal levels was seen lowering wheat crop quality by exposing plants to the possibility of disease or sprouting as well as reducing bushel weights.

Overall conditions of both the winter wheat crops and the spring wheat crop were about steady compared with the previous week, the U.S.D.A. said.

A total of 74% of the corn crop in the 18 major states was rated good to excellent as of June 22, down from 76% the previous week but well above 65% the same week a year ago.

In top-producing Iowa, 79% of the crop was rated good to excellent in the latest week, down from 83% the previous week. But other key corn states such as Illinois and Indiana showed rating improvements in the latest week, with the Illinois crop rated 78% good to excellent, up from 76% the previous week, and Indiana rated 74% good to excellent, up from 72%. Northern corn-growing states that experienced much of the recent rainfall showed mixed ratings results compared with the previous week. The U.S.D.A. pegged Minnesota at 70% good to excellent, down from 79% the week ended June 15. North Dakota, though, was rated 85% good to excellent, up from 84% the previous week.

The 2014 soybean crop was 90% emerged as of June 22, ahead of 79% a year ago and 87% as the five-year average, the U.S.D.A. said. The crop was 95% planted, a percentage point ahead of the average for the date.

Soybean condition ratings declined slightly in the latest week, with 72% rated good to excellent compared with 73% the previous week, but compared with 64% the same week last year, the U.S.D.A. said. Top-producing Iowa saw a decline to 76% rated good to excellent in the latest week, down from 79% the week ended June 15.

In Minnesota, where recent torrential rains far exceeded normal levels of precipitation, crop conditions declined more significantly. In the latest week, the U.S.D.A. said 64% of the soybean crop in Minnesota was rated good to excellent, down from 74% the previous week.

The hard red winter wheat harvest was progressing but was behind the average in some key states. The U.S.D.A. reported that top-producing Kansas made strong progress in the latest week with 24% of the crop harvested (up from 2% the prior week), but well behind the 34% average for the date. Oklahoma’s drought-reduced harvest was on track at 74% completed, equal to the five-year average for the date, and the Texas harvest was 69% completed, ahead of the 64% five-year average.

There were minor adjustments in winter wheat condition ratings in states where harvest had not begun or was in very early stages, with the overall 18-state (hard and soft wheat) good-to-excellent rating unchanged at 30% (44% poor to very poor).

Harvest in four of the major Central states soft winter wheat states — Illinois, Indiana, Missouri and Ohio — were behind the five-year averages for the date, the U.S.D.A. said. Michigan and Ohio were yet to begin combining as of June 22. Illinois was 20% harvested, down from the 31% average, while Indiana was 13% harvested compared with 22%. Missouri’s harvest was 29% completed, down from 47% as the average.

The spring wheat crop was 98% emerged in the six major states, three percentage points ahead of the 2009-13 average, and was 10% emerged, six points behind the five-year average, the U.S.D.A. said. Overall conditions in the six states were 71% good to excellent as of June 22, down from 72% the previous week but just ahead of 70% at the same time last year.