The Grain Industry Association of WA's yield report reveals the Esperance port zone had varying yield results in October.
GIWA found Esperance had "very good areas" along the coast, but it had "some very poor areas" in the north and north west.
The survey found coastal areas had a "dream run" due to an earlier start than most, little waterlogging and no frost.
"Grain yields for all crops will be above average and grain quality is expected to be good," GIWA said.
In contrasts, the results have been erratic away from the coast because of the dry spring and the influence of frost.
"The frost has taken the top off many barley and canola crops and grain yields swing wildly through paddocks," GIWA said.
"Most barley in the zone is grown for feed and the high screenings for many loads have been less of a problem than contamination from wheat volunteers.
"Canola grain yields in the better areas have been better than expected although in the north and eastern areas, the dry, frost and rain prior to harvest has resulted in some very poor yields and some undeliverable loads due to sprouting."
GIWA found there had been little wheat harvested and the estimated wheat tonnage was unknown.
The wheat crops were at a more vulnerable growth stage when the frosts hit and many were cut for hay.
Early results had found frost had more of an affect on wheat than expected and tonnage was likely to be lower than current estimates.