Vinpro Technical Harvest Report 2026

Climatic and viticultural trends

Bud break timing in the region was normal and comparable to long-term trends. Producers who pruned prematurely and applied dormancy-breaking agents indiscriminately reported poorer bud break. Those who waited for sufficient accumulation of chill units were rewarded with good and uniform bud break in their vineyards, which in turn resulted in improved crop expectations. During the 2025–2026 growing season, both maximum and minimum temperatures were noticeably higher compared with the 2024– 2025 season, resulting in higher average monthly temperatures. Elevated temperatures stimulated both vegetative and reproductive growth in vineyards, although not to the same extent as observed in other parts of the Boland. The timing of véraison and the first grape deliveries to the cellar was consistent with the previous year’s dates. Weather conditions in January and February were moderate, with the first significant heatwave recorded in March. During the eight-day heatwave, temperatures above 41 °C were recorded for five consecutive days, which is unprecedented for this area. This placed additional pressure on cellars to receive grapes timeously in order to prevent excessive sugar accumulation and weight loss.

The Olifants River region’s rainfall season commenced late, with only 3 mm recorded on 10 May 2025. The irrigation canal was out of operation

from 28 April to 12 May, during which producers indicated that soils had dried out considerably. From 12 May, the region experienced warm, dry easterly wind conditions that promoted leaf fall. The first effective rainfall was only recorded on 6 June, accompanied by significant cold conditions and snowfall on the Ceres and Worcester mountains. Thereafter, the region experienced good cold conditions, with frost and snow recorded on the mornings of 14 and 15 July (Figure OL 1) . Despite favourable conditions for chill accumulation, a brief warm period occurred during the week of 21 July, although this did not significantly offset the high levels of chill unit accumulation. On 1 August, the Department of Water and Sanitation opened the sluices of the Clanwilliam Dam, lowering the dam level to 75% capacity to allow construction work on the dam wall to continue. The dam level gradually increased over the course of the winter to 95%, where it was maintained. Consequently, producers received a reduced allocation of irrigation water for the season.

0 100 200 300 400 500 600 700 800 900 2024-06-01 2024-06-15 2024-06-29 2024-07-13 2024-07-27 2024-08-10 2024-08-24 Chill units (Utah model) Accumulation of chill units (1 Jun–31 Aug: 2024 vs 2025) Chill units (Utah model), 2024 Chill units (Utah model), 2025

Figure OL 1. Year-on-year comparison of chill unit accumulation (2024 vs. 2025), Vredendal, Olifants River.

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