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Summary
Models indicate a neutral chance of exceeding median rainfall for the South West Land Division (SWLD) for the November 2025 to January 2026, meaning extreme wet or dry conditions are unlikely, but a wide range of rainfall remains possible. Both day and night time temperatures are expected to be warmer than normal up to summer, December 2025 to February 2026.
Recent conditions
- After a dry start, rainfall from April to October was average to above average, with winter cold fronts and north-west cloud bands (associated with the negative Indian Ocean Dipole (IOD)) bringing additional late-season rainfall to the north-eastern and eastern parts of the SWLD.
- Nights below 2 °C from August to October were above average across much of the south-west. The Department of Primary Industries and Regional Development (DPIRD) weather station at Wickepin North recorded the highest number of nights below 2 °C at 42, which is 27 above the long-term average. Ravensthorpe was the coldest site, recording -3.8 °C.
- Maximum temperatures in early October were above average, with a brief period of high temperatures, particularly around Esperance. For the SWLD as a whole, October maximum temperatures were average to above average, while minimum temperatures were average to below average. Nights below 2 °C in Wickepin North were above what is normally expected for the time of year, with 12 nights below 2 °C 9 more than the 2000–24 average.
Outlook summary
Rainfall summary
1 April to 31 October rainfall map shows wetter conditions along the coast and drier conditions in the north and central SWLD. Margaret River weather station has recorded the highest rainfall total 1,299 mm. On the other end of the scale, Nungarin weather station has recorded 176 mm since April.
The rainfall decile map for the same period shows decile 8–10 the majority of the SWLD, with The Bureau’s Williams weather station at decile 1.
Figure 1: Rainfall (mm) totals for 1 April to 31 October 2025 in the SWLD. Margaret River has recorded the highest total of 1,299 mm, Nungarin the lowest with 176 mm.
Figure 2: Rainfall decile ranking map for 1 April to 31 October 2025 for the SWLD ̶ indicating decile 8–9 rainfall for the majority.
Number of nights below 2°C
Frost at flowering can affect pollen fertility, grain set, and grain size, thereby impacting yield. The number of nights below 2 °C provides an indication of frost risk. Maps of nights below 2 °C (frost occurrence) and minimum temperature (frost severity) are generated using data from 332 Bureau of Meteorology (BoM) and 191 DPIRD weather stations. Both sets of stations measure air temperature in a shaded enclosure (usually a Stevenson screen) at a height of approximately 1.2 m above ground level. A temperature of 2 °C at 1.2 m is roughly equivalent to 0 °C at ground level, which is cold enough to cause significant damage to cereal crops.
The number of nights below 2 °C from August to October 2025, compared with the 2000–24 average, indicates that for much of the SWLD, frost occurrence this year has been above average. Wickepin North recorded the highest number of nights below 2 °C, with 43, 28 more than the average of 15. Salmon Gums experienced the lowest minimum temperature of - 3.3 °C, which is 0.7 °C lower than the 2000–24 average of -2.6 °C.
DPIRD’s Extreme Weather Event Tool identifies which DPIRD weather stations have recorded frost-potential temperatures based on hourly data.
Figure 3: Number of days below 2 °C for August to October 2025 for the SWLD. DPIRD’s Wickepin North weather station recorded 43 nights below 2 °C.
Figure 4: Change in the number of nights below 2 °C in August to October compared to the 2000–24 average. Yilgarn 9 nights less, Wickepin North, 28 nights more.
Figure 5: August to October 2025 minimum temperature for the SWLD. Salmon Gums had the lowest minimum temperature of -3.3 °C.
Figure 6: Average minimum temperature in August to October 2000–24 for the SWLD. Salmon Gums has the lowest average minimum temperature of -2.6 °C.
French and Schultz potential yield for wheat
The potential wheat yield maps below represent the final maps for 2025, using April to October rainfall to determine the maximum possible wheat yield under ideal conditions, without additional constraints, it does not account for water logging. Potential wheat yield is estimated using the French and Schultz potential yield model, expressed as:
Yield (tonnes/ha) = WUE * (stored soil water + growing season rainfall - evaporation)
where WUE stands for water use efficiency, and growing season rainfall is typically measured from April to October. Stored soil water at the start of the growing season is estimated as one-third of the summer rainfall. These maps consider 2 different WUE values: 15 and 20 kg/ha/mm. The lowest yield potential, with a WUE of 15, is 1 t/ha at Nungarin, while the highest yield potential, with a WUE of 20 is 24.1 t/ha at Margaret River.
Figure 7: Potential yield map 2025, using French and Schultz equation, WUE 15 kg/ha/mm for the SWLD. Lowest yield potential is for Nungarin at 1 t/ha.
Figure 8: Potential yield map 2025, using French and Schultz equation, WUE 20 kg/ha/mm for the SWLD. Lowest yield potential is for Nungarin at 1.3 t/ha.
Rainfall outlooks
Three-month and single-month rainfall outlooks are derived from a range of national and international climate models. The outlooks are presented as the probability of rainfall being below, above, or neutral relative to the median rainfall. (Note: A neutral outlook suggests that extreme wet or dry events are less likely, and a wide range of rainfall amounts remains possible). To provide a more localised perspective, the SWLD has been divided into 2 regions, allowing for tailored rainfall outlooks specific to each area.
Figure 9: Rainfall outlooks are in 2 sections based on location in the SWLD ̶ the first group includes Central West and Central Wheatbelt forecast districts, while the second group covers Lower West, South West, Great Southern, South Coastal and South East Coastal forecast districts.
Rainfall outlooks for the Central West and Central Wheatbelt forecast districts of the SWLD
Single month
A summary of 14 national and international models shows that 8 models indicate chances of exceeding median rainfall for November 2025. This neutral model consensus applies for the remainder of the year and up until March 2026 (there is no model consensus for the 4 models that forecast ahead to April 2026). A neutral outlook suggests that extreme wet or dry events are less likely, and a wide range of rainfall amounts remains possible.
Figure 10: Single month model summaries of rainfall outlooks for the Central West and Central Wheatbelt forecast districts of the SWLD up to December 2025. Model consensus is for neutral chance of exceeding median rainfall for November and December.
Figure 11: Single month model summaries of rainfall outlooks for the Central West and Central Wheatbelt forecast districts of the SWLD up to April 2026. Model consensus is for neutral chance of exceeding median rainfall for January to March, with no model consensus for April 2026.
Three month
A summary of 17 national and international models shows that for November 2025 to January 2026, 11 models indicate neutral chances of exceeding median rainfall. There is also model consensus for neutral chances for summer, December 2025 to February 2026 and up to February to April 2026 (graph not shown). A neutral outlook suggests that extreme wet or dry events are less likely, and a wide range of rainfall remains possible.
Figure 12: Three month model summaries of rainfall outlooks for the Central West and Central Wheatbelt forecast districts of the SWLD up to summer, December 2025 to February 2026. Model consensus is for neutral chances of exceeding median rainfall.
Rainfall outlooks for the Lower West, South West, Great Southern, South Coastal and South East Coastal forecast districts of the SWLD
Single month
A summary of 14 national and international models shows that 8 models indicate chances of exceeding median rainfall for November 2025. This neutral model consensus applies for the remainder of the year and up until March 2026 (there is no model consensus for the 4 models that forecast ahead to April 2026). This neutral model consensus applies until the end of the year. A neutral outlook suggests that extreme wet or dry events are less likely, and a wide range of rainfall amounts remains possible.
Figure 13: Single month model summaries of rainfall for the Lower West, South West, Great Southern, South Coastal and South East Coastal forecast districts of the SWLD up to December 2025. The majority of models are indicating neutral chance of exceeding median rainfall until the end of the year.
Figure 14: Single month model summaries of rainfall for the Lower West, South West, Great Southern, South Coastal and South East Coastal forecast districts of the SWLD up to April 2026. Model consensus is for neutral chance of exceeding median rainfall for January to March, with no model consensus for April 2026.
Three month
A summary of 17 national and international models shows that for November 2025 to January 2026, 9 models indicate neutral chances of exceeding median rainfall. There is also model consensus for neutral chances for summer, December 2025 to February 2026 and up to February to April 2026 (graph not shown). A neutral outlook suggests that extreme wet or dry events are less likely, and a wide range of rainfall remains possible. It is important to note that forecast reliability decreases with longer lead times.
Figure 15. Three month model summaries of rainfall outlooks for the Lower West, South West, Great Southern, South Coastal and South East Coastal forecast districts of the SWLD up to summer, December 2025 and February 2026. Model consensus is for neutral chance of exceeding median rainfall.
Important disclaimer
The Chief Executive Officer of the Department of Primary Industries and Regional Development and the State of Western Australia accept no liability whatsoever by reason of negligence or otherwise arising from the use or release of this information or any part of it.
Copyright © State of Western Australia (Department of Primary Industries and Regional Development), 2025
