Bologna, September 4, 2026 – The first (and at this point seems real) turning point of this long scorching summer in Emilia Romagna finally has a date: all on Wednesday, September 9, when a North Atlantic depression could descend to more southern latitudes, eroding the northern edge of the African anticyclone bringing with it rain and thunderstorms, even strong ones, on the Alps, the Po Valley, particularly in the central-eastern sectors, and on Liguria, accompanied by a first significant drop in temperatures.
- Arpae forecasts
- The trend from mid-September
- A record summer
- Tropical nights and scorching days
- Bologna was the hottest city with 81 tropical nights and 46 scorching days
- Boiling sea and Sahara sand
- Nanni (Ampro): “Return towards typical climatic averages of the period”
Arpae forecasts
“The entry of disturbed Atlantic flows – it reads on the website of the Emilia-Romagna Environment Energy Prevention Agency – will favor unstable weather conditions in the regional territory associated with precipitation, also in the form of thunderstorms, especially towards the end of the period. Temperatures are expected to gradually decrease at the end of the period in maximum values, although remaining above the climatic average.” Between Thursday 10 and Friday 11, instability should gradually ease in the North and extend towards the Center and part of the South. The weakening of the anticyclone would thus favor a reduction in temperatures across the Peninsula. The transition from heat to cool, therefore, could be sharp, but it is not yet certain. “Temperatures are indeed expected to gradually decrease from September 9 – it further reads on Arpae –, but will still remain above the climatological average values.”
The trend from mid-September
“From Monday 14 to Sunday 27 September – writes Arpae – conditions of high pressure may alternate with the passage of disturbed waves linked to Atlantic currents passing south of the Alpine arc. This will result in a phase characterized by variability, with possible precipitation episodes interspersed with sunnier periods. Overall, rainfall amounts should remain around the period’s norm, while temperatures will tend to remain slightly above typical seasonal values.”
A record summer
Summer 2026 that has just ended was characterized by exceptionally high temperatures. With the end of August, the summer concluded with temperatures similar to those of 2003: in fact, there were 4 heat waves that made the three summer months among the hottest since 1961 both for minimum and maximum temperatures.
Tropical nights and scorching days
A separate chapter deserves the number of tropical nights, totaling 47, which represents, according to data from the Emilia Romagna Environment Energy Prevention Agency, the second highest value in the series, equal to 2022 and after 2003, when 59 tropical nights were observed, while the number of scorching days, totaling 32, is the highest in the series, with a difference of 5 days compared to 2012.
Bologna was the hottest city with 81 tropical nights and 46 scorching days
The urban area of Bologna – Arpae further writes – was the hottest in terms of minimum temperatures: the Arpae station, located in Piazza 8 Agosto, recorded 81 tropical nights, of which 24 nights had minimum temperatures above 25 °C. Regarding maximum temperatures, 46 scorching days were observed here, but higher values, even exceeding those of Bologna, were recorded in the central-western plain areas.
Boiling sea and Sahara sand
During the summer, sea surface temperatures progressively rose, reaching record monthly average values in August with increasing anomalies and values above the normal variability estimated over the 2008-2025 period in other summer months. Finally, it is worth recalling the intense Saharan dust transport event observed during the last days of August, coinciding with some of the hottest and most sultry days of the summer, which led to an increase in PM10 values.
Nanni (Ampro): “Return towards typical climatic averages of the period”
“After this long phase still fully summery in flavor, something could start to change right between the first and second ten-day period of September. The indication I am observing concerns a possible lowering of latitude of the Atlantic disturbed flow, which could favor the entry into the Mediterranean of relatively cooler and unstable air masses – explains Roberto Nanni, Ampro meteorological technician –. It would be an important passage because it could gradually bring atmospheric conditions back to characteristics more consistent with the period, after weeks characterized by temperatures well above typical seasonal values. However, we are still 7-9 days away from the possible change and, at this distance, it would be premature to go into details. Neither the dynamics, nor the timing, nor especially the intensity of the effects on Italy are yet sufficiently defined. What we can say today is that this possible evolution is beginning to emerge in the general lines of atmospheric circulation. So, if we look at the current average trend, the first element that emerges is mainly thermal: a progressive return towards values closer to the climatic averages typical of mid-September. To understand how significant this change will really be, we will have to wait a few more days.”
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