The Bureau of Meteorology (BOM) has warned Western Plains farmers of an increased risk of frost this season.

Frost is a common threat to crops in southern and central Australia from late autumn to early spring, bringing a crunch underfoot after a cold, clear night. But if you’re an agricultural producer it can strike a chill in more ways than one.

Frost can have a devastating effect on vegetation when ice forms on the surface of plants and also freezes their internal cells, causing the plant tissue to rupture.

Damage and associated financial losses depends upon frost severity—how quickly the temperature drops to 0 °C and the length of time it stays below it.

Plant type, variety, sowing date, nutrition, and stage of growth can all determine the extent of damage from frost.

Greg Rummery, an agronomist with Outlook Ag at Walgett agrees there are early indicators of potential frost issues in winter crops across the Western Plains, but that is not necessarily anything unusual in the local area. However, he said current dry conditions can make the severity of frost worse.

“It’s been pretty dry north of Coonamble,” Mr Rummery said. “Farmers haven’t started planting and in dry conditions frost is pretty normal.”

Experienced regional agronomist Greg Rummery. IMAGE: OutlookAg

Frost damage costs Australian agriculture millions of dollars each year not to mention pose a safety risk on the roads.

Australian National University (ANU) climate applications scientist Steven Crimp said some parts of New South Wales were now experiencing five more frost events on average each year, compared to 1960.

"I think this is one of those climate surprises," he said. "Despite the sort of overall warming trend in our temperatures, the extremes of our temperatures, be they hot or cold, are acting in a slightly more nuanced and complex way."

According to BOM, the winter long-range forecast shows warmer than usual daytime temperatures are likely almost everywhere, with cooler nights for western New South Wales, parts of southern Queensland, eastern South Australia and southern areas of the Northern Territory - ideal frost conditions.

Mr Rummery said frost will slow down development of emerging crops and damage crops which are further advanced.

“As an agronomist, I often see frost damage in the second half of August and into September when crops are running up to head. I think BOM are being cautious in their outlook, but farmers have always managed frost as best they can and have ways to mitigate the issues, such as cutting crops for hay.”

Emerging crops can be slowed by frost. IMAGE: OutlookAg

Bureau of Meteorology Extended Prediction Technical Lead Catherine Ganter said there was a high chance of below average rainfall, particularly in southern areas of Australia.

‘Southern areas have at least twice the normal chance of winter rainfall falling in the bottom 20 per cent of records,’ Ms Ganter said.

Ms Ganter said with drier conditions forecast, the risk of frost during winter, which is most common for southern and central Australia, was heightened for inland areas.

'Even though average minimum and maximum temperatures are expected to be warmer than usual this winter, there will still be times of cold wintry conditions. This can increase the frost risk when there are still nights that are clear of cloud cover,' she said.