Temperatures soared to close to all-time May records in southern regions on Monday as farmers through South Australia, the western Riverina and south-western and far western Victoria continued to wait for a break.

According to Bureau of Meteorology (BOM) data Port Fairy, on the Victorian south coast, pushed up to 26 degrees, within 2 degrees of its all time highest May temperature of 28, markedly above the long-term May mean of 16.8 degrees.

Across the border, South Australia's agricultural regions also had well above average temperatures, with Murray Bridge reaching 28.3, while in NSW's temperatures also reached 28, albeit at Smithville, in pastoral country north of Broken Hill.

While it is still early in the sowing window, the drying weather, eating up any small reserves of moisture from light falls in late April, combined with the medium term outlook is starting to raise concerns for croppers.

Through Victoria's west Wimmera there a concern that rain of 5-15mm over the past month may be just enough to have shot canola seed but not enough to sustain it, with some farmers already planning a resowing program.

In South Australia in particular there is the acknowledgement among the grain sector that markedly above average rainfall will be required from here on in just to achieve average yields, primarily due to the significant moisture deficits that have emerged over the past 18 months.

The story is not much better in western Victoria, especially the state's high rainfall Western District region, which is enduring the worst of the drought in terms of its rainfall as a percentage of normal.

A lack of rain at this time of year is more influential than at other times as it lowers the chance of crops germinating into warm soils and getting a head start before the cold conditions of winter.

The majority of weather models are forecasting no significant rainfall for the southern grain belt until at least mid-May.

It is part of the reason agricultural analysts, such as Tobin Gorey, The Watchlist newsletter, are placing the region on watch in terms of potential production issues.

"It is still very early in the season, but given the likelihood of crops not emerging until late May at the earliest we are going to be monitoring the region," Mr Gorey said in his most recent report.

However there is some tentatively positive, or least less negative, news coming out of the Bureau's most recent long-term rain forecast.

While the next two weeks have a markedly higher chance of being drier than usual, June is rated neutral in terms of exceeding the median rainfall, while June-August is now faintly positive in terms of above-average rainfall, although not to a statistically significant extent.