“The month of May in Sicily was also, as has been happening since September, significantly warmer than normal. While in the Central-Northern regions the long series of positive monthly thermal anomalies was interrupted thanks to continuous disturbances throughout the period, in Sicily a thermal trend persists in which the anomaly seems to have become the norm”.
This is what the Sicilian agrometeorological service states by analyzing the values of the Sias network. “This time no extreme heat peaks were recorded. The anomaly for the maximum temperatures recorded on day 9 on the occasion of the most important disturbed phase of the month was significant, the only phase significantly colder than normal – they add from Sias – The central period of the month was instead significantly warmer than normal, even on the occasion of the perturbed phase between days 18 and 19, associated with southern ventilation.
The regional average of the monthly average, based on Sias data, is estimated at 18.4 °C, approximately 0.9 °C higher than the norm for the period 2003-2022, but lower than the estimated maximum of 18.9 °C for 2006. The maximum monthly value on the Sias network of 35.8 °C was recorded on day 16 from the Enna district Pasquasia station (located downstream at a low altitude compared to the urban centre); the minimum monthly value of -0.8 °C was recorded by the Cesarò Monte Soro station (Me) on day 3″.
Meanwhile, the behavior of tree crops following the accumulation of such limited cold in the winter period is under observation. We are trying to understand whether the thermal anomaly had negative repercussions on the induction of flower buds, flowering and fruit set.
As an example, we show the trend of the accumulation of Cold Units calculated starting from the beginning of the cold period with the Weinberger method (number of hours with temperature below 7 °C) at the SIAS Mineo station (CT), illustrative of a generalized phenomenon on the regional territory.
Despite not having continuous hourly data available for the years preceding the SIAS series, the hourly data estimates made on the basis of historical daily data allow us to state that the 2023-2024 winter scenario is almost certainly completely new compared to meteorological history of Sicily.
It is stone fruit that is generally more sensitive when it comes to chilling requirements, so much so that in Sicily fruit growers have now acquired good experience in selecting varieties with low chilling requirements, which are better suited to the climate of the island.
However, even more typically Mediterranean crops such as vines and olives have their own sensitivity to the accumulation of cold, which is expressed with a different physiological response of some varieties/vines to the winter temperature trend.
