Related to the analysis I made for November 2018 in Treviso (N.E. Italy), one of the warmest recorded since 1973, here I am going to analyse the temperatures of the last 3 months, that is September, October and November (‘SON’ from now onwards) in order to evaluate if Autumn 2018 has been above or below the long term average (1981-2010) in Treviso.
In Figure1 the maximum and minimum temperatures average for SON in each year are shown. Like for November 2018 analysis, we can see how the average minimum temperatures tend to increase more in the last 20 years than the maximum values and Autumn 2018 shows the highest values.
In fact the long-term (1981-2010) Autumn average temperatures in Treviso are (9.63/18.76 °C) and the last Autumn has recorded (13.03/21.06 °C). The magnitude of the anomaly can be seen in Figure2, where the temperatures anomalies for each year (Autumn) are shown (for both maximum and minimum average values).
It is clear how this Autumn has observed the highest average minimum and maximum temperatures (+3.55/ +2.33 °C respectively) since 1973, with October the warmest recorded for the maximum values (anomaly +2.46 °C) and second for the minimum (anomaly +3.78 °C); also September was very mild, the 4th warmest for the maximum values (anomaly +2.78 °C) and 3rd for the minimum (+3.09 °C).
Considering the historical analysis, though this Autumn has been the warmest since 1973, however it is not the only one observing high temperatures (especially for the minimum values). In fact, from (Figure3) we can see how the years with minimum values above the average (anomaly higher than 0.5 °C) have consequently occurred since 2008, with no Autumn recording negative anomalies in the minimum average temperatures. Instead, in the 70s and 80s, most years observed lower values. Regarding the average maximum temperatures, there is more variability, with some ‘cold’ years in the 00s and ‘hot’ years in the 80s.
It would be interesting to understand why the minimum temperatures observe a higher (positive) anomaly than the maximum values and for more consecutive years; it might be due to an increase in the overcast conditions during the night which might have led to a decrease in the radiative cooling at surface.