Italy stays sunny until 28 October, then cooler air and rain may arrive

Stable and sunny until Wednesday

A high-pressure system over the Mediterranean is expected to keep most of Italy stable and sunny from Monday 26 October through Wednesday 28 October, according to forecasts from Federico Brescia of iLMeteo.it. On Monday the North should see mostly clear skies, a cool morning and some local fog, while the Centre remains settled and sunny. In the South and on the islands, sunshine comes with strong northerly winds and a few showers over northern Sicily. Tuesday 27 October brings stable weather to the North, rising maximum temperatures in the Centre and strong Grecale winds in the South. On Wednesday 28 October the forecast shows stability in the North, mostly clear skies in the Centre and clear or partly cloudy skies in the South, where Grecale winds stay brisk. La Repubblica describes the system as a block that keeps Atlantic disturbances from the west away from much of the country.

Brescia summarised the structure of the week in these words.

“The week that will carry us into early November will be shaped by the consolidation of an anticyclonic structure over the Mediterranean basin.”

Sharp swings between day and night

Overnight and at first light, minimum temperatures are forecast at 5-8°C in inland plains and valleys, where some fog cannot be ruled out. By midday, sunshine should push maximums above 16-17°C, with peaks of 20°C on the flat and valley zones of the Tyrrhenian Centre-South, according to iLMeteo.it. Il Giornale, which reported on the opening days of the week, said many minimums had fallen below 10°C at dawn, especially in the Centre-North. The same outlet put expected daytime highs above 20°C, particularly in the Centre-South and on the islands, a higher band than the 16-17°C iLMeteo gave. Both outlets agree that the gap between cold nights and warm afternoons is the defining feature of the week.

Cooler air and rain from Thursday

The stable run ends gradually. Thursday 29 October brings more cloud cover from the north-east, which il Giornale calls harmless, along with a first sign of less stable weather. Friday 30 October brings more clouds and rain on the Adriatic side and in the South, while the North and the Tyrrhenian regions stay drier for longer, partly shielded by the Apennines. For the weekend of 31 October to 1 November, the North could also see clouds and rain as the anticyclone weakens and a possible vortex forms over the Mediterranean, although il Giornale says this still needs confirmation from later model updates. Brescia's outlook carries the same caveat, since the weekend picture may still shift. He described the expected change in these terms.

“a cooler air mass descending from the north-east will enter the national territory more decisively, bringing instability and some rain to the Centre-South.”

The polar vortex question

Meteorologists at 3BMeteo, quoted by il Giornale, are studying the polar vortex, the large wind system that circles the North Pole high in the atmosphere during winter. Model updates suggest it could weaken noticeably and change shape between late October and early November. When the vortex is weaker, cold air can sometimes move toward Europe and occasionally the Mediterranean, though the outlet stresses this is not a fixed rule. So far, no equally clear response has appeared in the circulation close to the ground. No source ties the vortex signal to a specific date or area.