All stonefruit varieties require a certain amount of chilling over the dormant period to properly reset the tree for a strong start to spring. The impact of winter chill on the timing and intensity of flowering is a little more complex than the simple measures of chill accumulation but it’s a good guide for comparing winters.
The earliest and strongest seasons occur when there is high winter chill early on and then once the trees have had enough chill hours, warming temperatures accelerate bud emergence. that’s why a high chill year doesn’t necessarily mean an early start to flowering if it remains cold coming onto spring.
The chill data is available on the Summerfruit NZ member provided by HortPlus.
Hawke’s Bay: similar chill to last year which was right about in the middle – between a high chill and early spring in 2024 and a low chill and late spring in 2023.
Marlborough: lower chill compared with the last two years, more in line with 2022 and 2023.
Central Otago: never struggles to have sufficient chill accumulation so the results are unlikely to have any real implications but interestingly the winter chill is tracking below average compared with previous winters. Anyone who’s been working outside in Otago will rightfully disagree with this because it was colder than average in May and there were plenty of cold days in June but the chill accumulation model I’ve used only counts hours in the sweet spot when temperatures are either side of 4°C and can go backwards when it too warm.
Richardson Chill units to 22 July 2026
|
Station |
2023 |
2024 |
2025 |
This year |
|
Hawke’s Bay |
||||
|
Bay View |
65 |
1040 |
841 |
806 |
|
Havelock North |
598 |
938.5 |
694.5 |
797 |
|
Marlborough |
||||
|
Renwick |
791.5 |
1194.5 |
1081 |
882 |
|
Otago |
||||
|
Cromwell |
1129.5 |
1007 |
1027.5 |
951 |
|
Roxburgh |
1253 |
1312 |
1186.5 |
1019.5 |