Climate data provides insights on current season
Summaries of the climatic conditions of the current growing season against the previous 3 seasons across all 9 of WA’s wine regions has been completed by the department's technical officer Yu-Yi Liao.
This analysis provides wine producers insights on how the current growing season compares to the previous 3 seasons (noting incomplete data set after 28 February 2025).
This summary includes bar graphs for each region illustrating monthly rainfall data for the last 4 seasons from June to May and line graphs showing accumulated growing degree days (GDD) (excluding March to May 2025).
A general rainfall observation for the current growing season is that all regions south of Peel experienced their highest monthly rainfall in August.
In terms of GDD, in all the regions except for Great Southern, the 2024-25 season to date has accumulated fewer GDD units compared to 2023-24. However, temperature still follows a higher trend line compared to seasons 2021-22 and 2022-23.
Swan District
Figures 1 and 2 show data collected from the BoM Millendon weather station (site number 9281) representing the Swan District wine region.
The average winter rainfall across the last 4 seasons was 375 mm, 2024-25 recorded the highest winter rainfall at 427 mm.
Current season accumulated GDD is tracking slightly lower than last season by 166 units as of 28 February. If this trend continues until the end of the growing season, it is likely 2024-25 will accumulate the second highest GDD over the last 4 seasons.
Perth Hills
Perth Hills' region data in Figures 3 and 4 are constructed from 2 weather stations, BoM station Bickley (site number 9240) and DPIRD station Glen Eagle.
2024-25 had a similar winter rainfall total as 2021-22, receiving 747 mm of rainfall and 723 mm respectively. Meanwhile, 2022-23 and 2023-24 marked 666 mm and 556 mm in comparison.
Accumulated GDD had a similar trend as Swan District with 2024-25 (1759 units) being 168 units cooler compared to last season as of 28 February.
Peel
Peel’s data in Figures 5 and 6 is sourced from BoM Dwellingup weather station (site number 9538).
Peel region experienced the driest winter in the last 4 years (466 mm) with lower than average rainfall in July and August.
At the end of February 2025, Peel had accumulated 1627 GDD, 162 units lower than this same time in the previous season.
Geographe
Data derived from DPIRD’s weather stations' Capel, Donnybrook and Dardanup 2 were compiled to represent Geographe in Figures 7 and 8.
In the 2024-25 season, the region had the highest winter rainfall (606 mm) compared to the previous 3 years with significantly higher rainfall in June and August.
Spring 2024-25 received consistent rainfall around 50 mm each month, whereas the previous seasons had variability across the spring months.
The current season accumulated GDD has tracked slightly higher (89 units difference) than 2021-22 and 207 units lower than season 2023-24 at the end of February.
Margaret River
Figures 9 and 10 illustrate Margaret River’s seasonal data from DPIRD’s Vasse, Wilyabrup, Margaret River, Rosa Brook and Karridale weather stations.
Margaret River experienced a spike in rainfall (302 mm) in August 2024-25 compared to the last 3 seasons, contributing to 2024-25 recording the wettest winter, while 2024-25 spring rainfall was less than the average but similar to 2023-24.
As of the end of February 2025, the current season had accumulated 1351 GDD units which is only fractionally higher than 2021-22. Based on this trendline, it is likely the current season will be similar to 2021-22 in terms of accumulated GDD.
Blackwood Valley
The data from BoM Bridgetown weather station (number 9617) and DPIRD station Nannup are illustrated in Figures 11 and 12, representing the Blackwood Valley wine region.
Like the Margaret River region, Blackwood Valley experienced high winter rainfall in 2023-24 due to August recording 243 mm, which is more than double the amount in contrast with the previous 3 seasons.
2024-25 accumulated GDD follows a lower trendline than the past season, recording 1528 GDD units, which is 145 units less than 2023-24. The trend lines show 2024-25 distinctly higher than 2021-22 and 2022-23.
Manjimup
The BoM weather station at Manjimup (site number 9573) and DPIRD’s Manjimup HRS station provided data to represent the growing seasons in Figures 13 and 14.
Similarly, Manjimup region experienced a particularly wetter August in 2024-25 in comparison with the previous seasons. Interesting to observe is the winter rainfall spikes across 3 of the seasons clearly occurred in different months, June in 2023-24, July in 2021-22 and August in 2024-25.
Up to the end of February, Manjimup marked 1387 GDD units in 2024-25; 105 units less than the previous season.
Pemberton
Data from DPIRD Pemberton weather station was collated in Figures 15 and 16.
In comparison to the previous 3 seasons, Pemberton experienced a drier start to winter but progressively caught up with high precipitation in August (362 mm).
Similar trend and comparison with most other regions in terms of GDD, with the 2024-25 season accumulating 1302 GDD units up to the end of February.
Great Southern
Multiple weather stations from the subregions of the Great Southern were combined to produce Figures 17 and 18. Those stations are BoM's Albany Airport (9741) and Rocky Gully (9964), Water Corporation's Quickup Dam and DPIRD's Denmark, Mt Barker, Stirlings South, Frankland North and Frankland weather stations.
The Great Southern region did not experience a high August rainfall this season like that seen in Geographe, Margaret River, Blackwood Valley, Manjimup and Pemberton. Accumulated rainfall as of February 2025 shows that the current growing season has experienced the lowest rainfall over the last 4 seasons.
Unlike all the other regions, the Great Southern has not accumulated less GDD units than 2023-24, meaning the region as a whole has experienced a similar warm season up to end of February 2025.
For further information on the data presented, contact Yu-Yi Liao.