The Piccadilly Valley weather station in the Tiers Vineyard is broken. We are flying weather blind although using the data from Mount Lofty (700metres ASL) the temperature summation from October to the end of February is 804.1°C days versus the long-term average of 743°C days (+8%).
The summation for The Tiers Vineyard 2 kilometres way at 400metres ASL and adjusted for lapse rate is warmer at 974°C days, also +8% warmer.
This surprising warmer result is consistent with Parawa on the Fleurieu Peninsula to the end of February, which is 935.75°C days versus the average of 906.75°C days (+3% warmer).
We all are aware of the absence of heat waves this past summer and of the record February rainfall. The overwhelming impression is of a very cool wet growing season. The facts defy the impression, not an unusual event for the human perception of weather.
The reason for the misperception is that daily maximum temperatures (day temperatures) have been uniformly cooler this growing season but daily minimum temperatures (night temperatures) have been warmer by a larger amount than the days have been cooler. The large amount of cloud cover associated with the moist tropical air inflows have blanketed the southeast of Australia and prevented the normal summer night radiation of heat to the night sky keeping nights warmer and days cooler.
The result will be a vintage that reflects the cool days as refinement, elegance and fragrance of fruit combined with significant texture and tannins at lower alcohols, the effect of warmer nights.
The 2011 vintage will reflect the human perception of coolness rather than the meteorological fact of warmth to the benefit of wine quality.