The effect of the heat is evidenced in the Wimmera where crops that had not been windrowed by the time the heat came estimated to have yields drop from more than 2.5 tonnes a hectare to about 1t/ha.

The heat had little impact in the Mallee, while in the North East and Central North, yields were knocked back by around 15% by the heat.

In the Western District, where the heat was not as strong and there were still sufficient sub soil moisture reserves, the yields held up.

Despite a reduction in overall state yield of around 13pc, if the current estimate of 390,000t comes to fruition, it will be the highest yield in six years, and tonnage which has only been exceeded twice in the last decade.

In northern NSW, yields overall have ranged from 1.2t/ha to 2t/ha with oils levels ranging from 33 per cent to 42pc due to poor moisture profile throughout much of the season.

Moving south, the October frosts have proven to be a slightly more extensive than initially thought, which has affected the top and bottom of pods during grain formation.

The subsequent hot and dry finish has resulted in smaller than ideal seed size in many crops especially those sown at the later end of the sowing window.

Areas around Cootamundra were spared much of the end-season poor weather, with some oil yields reported up to 45pc, like the north, much of the south of the state achieved below average yields and oil yield.

Many growers in NSW are reported to be questioning the role of canola in the rotation, after so many years of poor returns.

Given higher input costs required to grow canola compared to wheat, the availability of adequate financial resources to ensure crop input requirements are met will impact on grower intentions next year.

The South Australian situation is not significantly changed from last month, with much of the canola harvested before the heat-wave conditions arrived. Good yields have been reported, with oils content ranging from 38pc to 49pc.

In Western Australia, the harvest is nearly complete, with the last of the grain still being shipped in the Albany zone.

Despite the impact of frost and moisture shortages in some isolated areas, overall the result is stronger than anticipated last month, with another 50,000 tonnes added to the projection.