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Seasonal Climate Outlook

August 2025

Summary

The rainfall outlook for August to October 2025 shows model consensus for above median rainfall across the South West Land Division (SWLD). Temperature outlooks indicate that warmer-than-normal temperatures will persist.

Recent conditions

The number of nights below 2°C in July was above the 2000-24 average for the SWLD. The coldest location was the Department of Primary Industries and Regional Development (DPIRD) Jingalup weather station, with 15 nights below 2°C and a minimum of -4.5C.
July rainfall was above average across much of the SWLD. A series of cold fronts brought heavy rain and hail to the west coast and along the south coast.
The latest DPIRD plant available soil water map shows good soil moisture levels in the south west corner and parts of the Central West and South East Coastal forecast districts. The Central Wheatbelt and Great Southern generally have low soil moisture levels.
The Southern Annular Mode is forecast to be positive for the first half of August, and then to be neutral for the rest of the month. This indicates that the first two weeks of August maybe drier than usual, before cold fronts return to a normal winter pattern.

Outlook summary

Rainfall summary

1 April to 30 July rainfall map shows wetter conditions along the coast and drier conditions in the north and central SWLD. DPIRD’s Margaret River weather station has recorded the highest rainfall total 860 mm. On the other end of the scale, DPIRD’s Bonnie Rock weather station has recorded 77 mm since April.

The rainfall decile map for the same period shows decile 8-10 for parts of the Central West, South West, Great Southern, South Coastal and South East Coastal forecast districts, decile 2-3 for parts of Lower West eastern parts of Great Southern and parts of the Central Wheatbelt forecast districts, and decile 4-7 (average) for elsewhere.

Figure 1: Rainfall (mm) totals for 1 April to 30 July 2025 in the SWLD. Margaret River has recorded the highest total of 860 mm, Bonnie Rock the lowest with 77 mm.

Figure 2: Rainfall decile ranking map for 1 April to 30 July 2025 for the SWLD ̶ indicating mixed rainfall, wetter conditions in the South East Coastal and eastern parts of the Great Southern forecast districts, average to drier elsewhere.

Plant available soil water map

The current plant available soil water map, averaged over 10 soil types and produced using the FAO crop factor method ̶ a standard approach for estimating crop water use (evapotranspiration), based on the FAO-56 guidelines developed by the Food and Agriculture Organization of the United Nations ̶ indicates high levels of plant available soil water along the west and south coast. Low levels are indicated for in the Central Wheatbelt and Great Southern. For more information see DPIRD’s soil water tool.

Figure 3: Plant available soil water map for the SWLD as of 30 July 2025 using FAO crop factor. Indicating high soil water along the west and south coast, and lower levels in the central grainbelt.

Number of nights below 2°C

The number of nights below 2°C provides an indication of frost risk. These maps are generated using data from 332 Bureau of Meteorology and 191 DPIRD stations. Both sets of weather stations measure air temperature in a shaded enclosure (usually a Stevenson Screen) at a height of approximately 1.2 m above the ground. A temperature of 2°C at 1.2 m is equivalent to 0°C at ground level, which is cold enough to cause significant damage to cereal crops.

In July 2025, the number of nights below 2°C was generally above the 2000-24 average. For example, the DPIRD weather station Yuna North East recorded 10 nights below 2°C, which is 8 more than the average for that period. DPIRD’s Jingalup weather station recorded 18 nights below 2°C, and a minimum temperature of -4.5°C. DPIRD’s extreme weather event tool identifies which DPIRD weather stations have recorded frost potential temperatures based on hourly data.

Figure 4: Number of days below 2°C for July 2025 for the SWLD. DPIRD’s Jingalup weather station recorded 18 nights below 2°C, and a minimum temperature of -4.5°C.

Figure 5: Average number of nights below 2°C in July for the years 2000-24 for the SWLD. The July 2025 map is greater than these averages.

The average number of nights below 2°C for August (2000-24) shows a similar spatial pattern to the July average map. The location with the highest number of nights below 2°C is York with 12. With above average rainfall likely in August – according to the majority of climate models - increased cloud cover is likely to reduce frost potential across the SWLD.

Figure 6: Average number of nights below 2°C in July for the years 2000-24 for the SWLD. York has the highest number, with 12 nights below 2°C.

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 South West Land Division has been divided into 2 regions, allowing for tailored rainfall outlooks specific to each area.

Figure 7: Rainfall outlooks are in 2 sections based on location in the SWLD ̶ first group includes Central West and Central Wheatbelt forecast districts, second group includes 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 15 national and international models shows that 9 models indicate above median rainfall outlook for August 2025. This above median model consensus also applies for September. For the rest of the year, model consensus is for neutral chances of exceeding median rainfall for October to December. A neutral outlook suggests that extreme wet or dry events are less likely, and a wide range of rainfall amounts remains possible.

Figure 8: Single month model summaries for rainfall for the Central West and Central Wheatbelt forecast districts of the SWLD up to December 2025. Model consensus is for above median rainfall for August and September, and then neutral chance of exceeding median rainfall for October, November and December.

Three month

A summary of 17 national and international models shows that for August to October, 11 models indicate above median rainfall. For the rest of the year and into January 2026, model consensus is for neutral chance of exceeding median rainfall. A neutral outlook suggests that extreme wet or dry events are less likely, and a wide range of rainfall amounts remains possible.

Figure 9: Model summary of rainfall outlook for the Central West and Central Wheatbelt forecast districts of the SWLD up to November 2025 to January 2026. Model consensus is for above median rainfall for August to October and then neutral chances of exceeding median rainfall up to November 2025 to January 2026.

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 15 national and international models shows that 8 models indicate above median rainfall for August 2025. Model consensus is then for a neutral outlook for the rest of the year, suggesting that extreme wet or dry conditions are less likely, with a wide range of rainfall outcomes remaining possible.

Figure 10: 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 above median rainfall for August and then neutral chances of exceeding median rainfall for September through to December.

Three month

A summary of 17 national and international models shows that 10 models indicate above median rainfall for August to October. Model consensus is for neutral chance of exceeding median rainfall for October to December and November to January. A neutral outlook suggests that extreme wet or dry events are less likely, and a wide range of rainfall amounts remains possible. There is no model consensus for spring, (September to November). It is important to note that forecast reliability decreases with longer lead times.

Figure 11: Three month model summaries for rainfall for the Lower West, South West, Great Southern, South Coastal and South East Coastal forecast districts of the SWLD up to November 2025 and January 2026. Above median outlook for August to October, neutral outlook for October to December and November 2025 to January 2026.

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.