Rainfall, decile, soil moisture and yield potential update, June 2026

Key messages

• Reasonable falls in February, March and May have supported 2026 crop establishment, while mild conditions have encouraged early growth.
• Soil moisture is variable across the Riverine Plains.
• There are a range of possible yield potentials which will be determined by rainfall as the season progresses.

Rainfall and deciles to date across the Riverine Plains

We've compiled a summary of rainfall and decile data for a number of monitor sites across the Riverine Plains.

Table 1 Rainfall and deciles by month at locations across the Riverine Plains (Source, BoM, Riverine Plains Weather, ARM online)

The year began with extremely dry conditions across the region, with lowest on record (LOR) to decile 2 rainfall received in January. The absence of the usual summer storms meant stored soil moisture remained low, although the general lack of weed spraying was welcomed by farmers.

Reasonable falls were recorded in February, depending on which storm you were under. Rutherglen received decile 9 for the month (68 mm) while Culcairn was lowest at decile 5 (21 mm). The lack of stored soil moisture and low water storage in dams used for livestock was of significant concern to farmers at the time.

March saw some good totals, with most sites moving into much wetter deciles (decile 9 to 10) across the region. This enabled early pastures, grazing cereals and canola to be sown,  although soil moisture remained low. Notable falls for the month were 110 mm at Culcairn (decile 10),  69mm at Urana (decile 9) and 95 mm at Rutherglen (decile 9), with other monitor sites falling in-between.

April rainfall was below average, with Decile 1 at Urana and decile 2 at Yarrawonga and up to Decile 4 at other locations.

May delivered a proper break, with solid falls across most of the region. Decile 8 rains were recorded at Rutherglen (77 mm) & Culcairn (76 mm), with decile 9 at Urana (72 mm). Less was received in southern areas including Miepoll (48 mm), Dookie (41 mm) and Yarrawonga (34  mm).

Although this data is only complete to 9 June (deciles unavailable), the month has so far delivered some good falls, from 54mm at Miepoll to 33 in Yarrawonga, Rutherglen and Culcairn, with Urana slightly drier. 

This brings growing growing season rainfall to 130 mm at Rutherglen, 70 mm at Yarrawonga, and 88 mm at Urana. 

Warm/mild conditions have supported early crop growth, especially when sown early.

Soil Moisture: Burramine, Rutherglen and Culcairn 

The below summed soil moisture graph shows moisture from 30-140cm depth at Burramine (Source: Riverine Plains Weather).

The green line shows summed soil moisture from June 2025 to June 2026, while the aqua line shows the theoretical field capacity (or saturation) and the red line is the crop lower limit, below which crops struggle to extract water (noting this is a relatively new moisture probe, with upper and lower limits still being confirmed). Rainfall events are represented by the blue columns along the bottom. 

The graph shows that while some December 2025 rainfall was stored, March rain has been the main driver of stored soil moisture in 2026, however, this really only reached 60-70 cm. May rains only penetrated to around 50cm. Overall, soil moisture is lower than at the same time last year. 

We estimate this site is currently around 50% full. In contrast, the Ag Vic Moisture monitoring site at Youanmite is reading around 90% full, to 120cm. 

At Rutherglen, March and May rainfall events added good moisture, so that stored soil moisture is currently slightly higher than this time last year. Rutherglen soil probes to 140 cm showed a response to March rainfall to 60 cm, while the May rains infiltrated to 120 cm. 

The Culcairn site has also improved since January, mainly after rainfall in March and May, being only slightly below the same time last year. May moisture penetrated to at least 90 cm, with small ingress below this depth.

Overall, conditions have improved since autumn, but rainfall and stored moisture are still quite uneven across the Riverine Plains, with some areas being quite wet, and others quite dry.

Yield potential

The following tables uses the French & Schultz equation with rainfall to date, an evaporation figure of 110 mm and stored soil moisture of 50mm to estimate some potential yields based on a decile 1, 5 and 8 rainfall finish to the season. 

For a decile 1 scenario, we’d expect a minimum of 80 mm rainfall at Miepoll, 84 mm at Dookie, 70 mm at Yarrawonga, 93 mm at Rutherglen, 90 mm at Culcairn and 50 mm at Urana, to the end October. For context, a decile 8 rest of the season would see 379 mm fall at Miepoll, 415mm at Culcairn and 304 mm at Urana. 

Table 2: Wheat yield potential (t/ha) for a range of locations across the Riverine Plains assuming a decile 8, 5 or 1 finish, assuming a WUE of 20 kg/ha/mm.

Decile 8 wheat yields range from 9 t/ha at Rutherglen through to 6.5 at Urana .Decile 5 yields are in the range of 6.1 at Rutherglen, to 4.9 at Miepoll and Dookie and 3.8 t/ha at Urana. Decile 1 wheat yields range from 0.9 t/ha at Yarrawonga, through to 2.4 t/ha at Culcairn.

For canola, using water-use efficiency of 10, the decile 8 yield potential ranges between 4.5 t/ha at Rutherglen and 3.2 t/ha at Urana. At decile 5, potential yields range from 1.9 t/ha at Yarrawonga and Urana to 3.1 t/ha at Rutherglen. At decile 1, canola yield potential ranges from 1.3 t/ha at Rutherglen, 1.2 t/ha at Culcairn and 0.5 t/ha at Yarrawonga.

Table 3. Canola yield potential (t/ha) for a range of locations across the Riverine Plains assuming a decile 8, 5 or 1 finish, assuming a WUE of 10 kg/ha/mm.

In summary, there’s quite a bit of variation across the region, both in terms of stored soil moisture and yield potentials. Which yield scenario eventuates will depend on how the season plays out, remembering that seasonal forecasts represent chances, not absolutes.

Riverine Plains will  revisit these yield potentials later in the year.

Acknowledgements

This data was collated as part of a project supported by the Victoria Drought Resilience Adoption and Innovation Hub (VicHub), which received funding from the Australian Government’s Future Drought Fund . Riverine Plains is the North East VicHub node lead.