As we head into late summer, agricultural interests in parts of Canada, thenorthern Plains and Upper Midwest become most concerned with the threat for anearly season frost as crops head toward maturity. There are a variety of cropsgrown; here are some of the major ones:Southern parts of Alberta, Saskatchewan and Manitoba are a major growing areafor spring wheat, canola and barley. The harvest tends to come anywhere fromearly August to early October, depending on how well crops have progressed.
Most of the corn and soybean production in Canada comes from southeasternOntario and southern Quebec. Harvests tend to come in anytime from earlySeptember to early November, although most of this region can expect toexperience frost and the threat for freezing temperatures by the middle to endof October.The northern U.S. Plains and Rockies, from eastern Idaho and Montana throughwestern Minnesota, grow more than 90 percent of the nation's spring wheat.

Harvests tend to run from early August to the middle of September. By earlySeptember, though, much of this region can expect to experience some frost--theaverage date for first frost in Bismarck, N.D., is Sept. 7.

A variety of crops are grown from the eastern Dakotas and Nebraska through theUpper Midwest, lower Great Lakes and Ohio Valley, but the two most significantcrops are corn and soybeans. Most of these areas will normally experience thefirst frost of the fall in October, although parts of the Upper Midwest willhave a frost earlier--for example, Minneapolis, Minn., averages a first frostin mid-September.

A deep upper-level trough will swing through the Great Lakes this weekend, andcool high pressure in its wake will make for very chilly conditions acrossparts of the Upper Midwest and Canadian Prairies. A light frost is possible onSaturday night in the wheat, canola and barley areas of eastern Saskatchewanand Manitoba. This is just a reminder that as we near the fall months, farmers'concerns shift from the threat for drought or extreme heat to the potential fora killing frost or freeze before their crops are out of the ground.

Story by AccuWeather.com Senior Meteorologist Bob Tarr