Farmers in Western Canada's Prairie provinces are counting on rains forecast by the weekend to salvage crops struggling to grow after weeks of dry weather.

Most arable land in Saskatchewan and Alberta, Canada's two largest producers of canola and wheat, have received less than 40 percent of average precipitation for the month ended June 7, according to Agriculture and Agri-Food Canada.

Some areas haven't received a drop in more than a month, said Clint Jurke, agronomy director at the Canola Council of Canada. The country is the world's biggest producer and exporter of canola, used to make vegetable oil.

Canola has also suffered damage from flea beetles and cutworms, and widespread frost in late May killed crops across a large area. That forced farmers to conduct one of the Prairies' largest re-plants in recent memory, Jurke said.

"A good general rain could fix most of these problems if that comes in the next two weeks. What the ultimate outcome is going to be on final production is anybody's guess."

About half the Prairies should receive rain by the weekend, including dry zones in central and northern Alberta, south-central Saskatchewan and north-central Manitoba, said Drew Lerner, president of Kansas-based World Weather Inc.

Amounts between Tuesday and Sunday may range from 5 to 20 millimeters (0.2 to 0.8 inches), he said.

"Nobody's getting a big soaking."

Temperatures should cool favorably by the weekend and a second round of rain may move through next week, Lerner said.

Most farmers managed to re-plant fields, Jurke said, despite seed shortages in some areas. But much canola seed was planted into dry soil and hasn't germinated, leaving fields patchy.

Rain in the next week could start those plants growing, but farmers may have crops growing at two different development stages, making harvest a challenge, he said.

ICE Canada November canola futures have gained 10 percent since mid-May, when the first frost hit Manitoba. Minneapolis September spring wheat futures have risen 9 percent in June.

Elmer Guelly has farmed near Westlock, Alberta for 46 years, and never seen his wheat and canola fields this dry in spring.

"They're badly in need of rain."

He is optimistic about his crops, but notes that forecasts have often been wrong lately.

"We'll believe it when we see it ... Right now we need a good two-inch soaker to bring them back to life."