Phenology is the study of periodic plant and animal life-cycle events and how these are influenced by seasonal and interannual variations in climate. In the case of the grapevine, the different development stages are known as bud break, flowering, fruit set, veraison, harvesting – when the grapes are mature – and leaf fall.
In 2014, these biological phenomena occurred earlier. Thus, in Luján de Cuyo, Malbec bud break took place in the last week of September, whereas in the Uco Valley, it came in the first week of October. In spite of this – and thanks to the absence of late frosts – there was a steady bud growth. The flowering stage of this variety occurred at beginning of November in Luján de Cuyo and in the second week of November in the Uco Valley, just confirming that it was a premature year, with dates advanced by 7 to 10 days. Veraison was ahead of historical normal dates, too. Finally, harvest also came about a week earlier and this – together with the rains in February and March – accelerated the entry of the grapes in the winery to avoid rot risks. For this reason, the harvest in Mendoza was carried out – on average – on April 20, about 10-14 days earlier than usual.
The year was quite normal in terms of the temperatures recorded both in spring and in summer. A special feature that we can mention is that the maximum temperatures in January and February were slightly lower than the historical average, while both the minimum and maximum temperatures in March and April were higher than the historical values recorded. In Gualtallary, Tupungato, the average temperature for the whole season was 18.1 °C / 64.58 °F (historical average: 18.0 °C / 64.4 °F), whereas in Ugarteche, Luján de Cuyo, it was 20.1 °C / 68.18 °F (historical average 19.8 °C / 67.64 °F). The following graph shows the monthly evolution of minimum and maximum temperatures in Gualtallary.
Spring started with a very dry climate, and later – similarly to what happened in the 2014 harvest – it gave way to a summer with more rain than usual, especially in January, February and March. This made planning the grape harvest a big challenge. Considering this situation, when deciding the harvest date, the health of the grapes took priority over their level of ripeness. At the end of the season, the rainfall recorded between October and April in Gualtallary, Tupungato, was 336 mm / 13.22 in (historical average 236 mm / 9.29 in), while in Ugarteche, Luján de Cuyo, it amounted to 327.6 mm / 12.89 in (historical average 247.35 mm / 9.73 in). The following graph shows the rainfall recorded on a monthly basis during the last season and the historical average.