The heat is taking its toll on the grape harvest in Menindee.
Growers have been watering more than normal and later in the day to keep the humidity high under the vines.
This keeps the grapes cool, but grower Paul D'Ettorre says it also means using more expensive electricity at peak times.
As for heat damage, he says it will only be possible to see how much has been done when the leaves are lifted for picking.
"That's when we're really going to see what heat damage has been done," Mr D'Ettorre said.
"At the moment we're all leaving a long draping canopy that makes a nice big umbrella to trap the humidity in and help keep the vines cool and help keep the grapes cool."
Mr D'Ettore is now expecting to pack about 120 tonnes of grapes this year - 20 less than he had hoped.
He says the vines worst affected by the heat are those already below their best.
"There is a little bit of heat damage coming through, mainly in the poorer grown grapevines - the ones that have struggled with other things going on - with salt damage and other things happening left over from the drought," he said.
"Those vines have seen a little bit more damage than what we would have liked."
The Bureau of Meteorology is forecasting temperatures above 40 degrees across the far west this weekend - including 48 degrees in Tibooburra.
There is a total fire ban across NSW today, as well as for the north-east pastoral district of SA.
© ABC 2013
16:48 EST Patches of good rain in southern parts of Western Australia has got the tractors rolling and some grain farmers are starting to put in this year's crop.