Grain growers in Western Australia are unsure they can replicate 2011's favourable production what with a persistent dry weather coupled with frost that could possibly affect overall grain yield for 2012- 2013.

Grain yields could drop by as much as 40 per cent, projected Max Johnson, grain operations manager at CBH Group, the state's biggest handler. This could mean that Australian grain growers could lose riding on the spike in prices of grain crops amid bad weather conditions that are likewise affecting the rest of the world, particularly the U.S. Midwest.

Global prices of grain have jumped, steered by a 55 per cent increase in corn prices, as drought across the U.S. Midwest over the past six weeks destroyed crops, thus affecting yields figures in what initially was expected to be a bounty harvest.

From the record harvest of 15 million metric tonnes in 2011/12, WA's grain output could decelerate to a dismal estimate of between 9 million to 11 million metric tonnes in 2012-2013. What's more, majority of the crop, or 65 per cent to 70 per cent, may be wheat, not grain, Mr Johnson added.

According to the Australian Bureau of Meteorology, from April to June, WA experienced below-average rainfall while July had likewise been exceptionally dry. It also did not help that the state had cooler than the normal minimum temperatures from January through June, the bureau added.

"We need an extended rainfall all the way through the end of September to even try and get it back on track," Mr Johnson told Bloomberg News. "We've seen frost after frost after frost all the way over the Wheatbelt that has retarded growth or put it in dormancy. That's hurting us."

According to data released in June by the Australian Bureau of Agricultural and Resource Economics and Sciences, Australia may only get to produce 24.1 million metric tonnes of wheat in 2012- 2013, down 6.2 per cent from an earlier estimate, and definitely less than last year's record 29.5 million metric tonnes crop. From 11.7 million metric tonnes a year earlier, WA may only gather 8.7 million metric tonnes of wheat this year.

The dry weather during 2010-2011 had slashed WA's wheat production by 38 per cent.

Australian harvest season usually starts in October. It was the world's No.2 wheat exporter in 2011/12. WA, on the other hand, is its biggest grain growing region.