Margaret River, WA, Australia / Chardonnay Grape
Total GDD:
2825
(Feb 12)
Day 196 / 243 (81%)
Current Season
Total GDD:
2825
(Feb 12)
Method: 50°F Sine
7-Day Daily Avg: 20.1
7-Day Projection: 2966 by Feb 19
Season: Aug 01, 25 - Mar 31, 2026
Key Freeze Dates (32°F)
Last Freeze:
10%: -- (rarely occurs)
50%: -- (rarely occurs)
90%: -- (rarely occurs)
10%: -- (rarely occurs)
50%: -- (rarely occurs)
90%: -- (rarely occurs)
First Freeze:
10%: -- (rarely occurs)
50%: -- (rarely occurs)
90%: -- (rarely occurs)
10%: -- (rarely occurs)
50%: -- (rarely occurs)
90%: -- (rarely occurs)
Growing Degree Days (GDD) track heat accumulation to predict when plants reach growth stages, pests emerge, and diseases become active.
Thresholds mark specific GDD values when events typically occur, with crossing dates showing when your season reaches each milestone.
Thresholds & Notes
Budbreak (E-L 4)
180
°D
Aug 21, 2025
|
Aug 20, 2024
|
Aug 24, 2023
|
Aug 26, 2022
Growth Stage
Margaret River frost-free advantage. Protect from ocean winds. Eutypa treatment window.
10 cm Shoots (E-L 12)
380
°D
Sep 19, 2025
|
Sep 10, 2024
|
Sep 13, 2023
|
Sep 20, 2022
Growth Stage
Powdery mildew spray program begins. WA maritime conditions require sulfur rotation.
Inflorescences Clear (E-L 17)
650
°D
Oct 12, 2025
|
Oct 6, 2024
|
Oct 7, 2023
|
Oct 20, 2022
Growth Stage
Margaret River Chardonnay shoot thinning. Pre-flowering fungicide critical.
Flowering (E-L 23)
900
°D
Nov 3, 2025
|
Oct 26, 2024
|
Oct 24, 2023
|
Nov 11, 2022
Growth Stage
No sprays during Cabernet Sauvignon flowering.
Fruit Set (E-L 27)
1150
°D
Nov 20, 2025
|
Nov 14, 2024
|
Nov 9, 2023
|
Nov 30, 2022
Growth Stage
Western Australia bunch thinning window. Target 8-10 t/ha premium Cabernet.
Bunch Closure (E-L 33)
1550
°D
Dec 13, 2025
|
Dec 3, 2024
|
Nov 29, 2023
|
Dec 22, 2022
Growth Stage
Final botrytis spray Margaret River vineyards. Marri flowering reduces bird pressure.
Veraison (E-L 35)
1950
°D
Jan 2, 2026
|
Dec 21, 2024
|
Dec 20, 2023
|
Jan 12, 2023
Growth Stage
Begin Baumé testing Margaret River Shiraz. Cool nights preserve natural acidity.
Berries Ripe - Chardonnay (E-L 38)
2400
°D
Jan 23, 2026
|
Jan 13, 2025
|
Jan 9, 2024
|
Feb 2, 2023
Growth Stage
11-12° Baumé. Acid retention critical in hot years.
Berries Ripe - Cabernet (E-L 38)
2900
°D
Feb 2, 2025
|
Jan 31, 2024
|
Feb 25, 2023
Growth Stage
13.5-14.5° Baumé. Multiple picks for premium parcels.
Late Harvest Complete
3200
°D
Feb 16, 2025
|
Feb 12, 2024
|
Mar 11, 2023
Growth Stage
13-14° Baumé. Tannin ripeness critical. Frost risk returning.