Heat in Italy: who measures it, and how hot

The Ministry of Health publishes daily heat wave bulletins for 27 Italian cities, issued Monday to Friday, and in 2026 they ran until September 20.

Who measures the heat, and what they watch

The bulletins are prepared by the Epidemiology Department of the Lazio regional health service and coordinated by the Ministry of Health, covering 27 cities. Behind them run two surveillance systems: daily mortality, through the SiSMG network, and emergency room admissions.

The populations they are written for are named: older people, people with chronic illness, children, pregnant women. The list of which 27 cities and the exact start date of the 2026 season sit on pages we could not open, so this page does not name them.

How hot is hot: mean July maxima from 61.2°F to 90.1°F

The 1991-2020 normals put the mean daily maximum in July at 90.1°F (32.3°C²) in Florence, 87.8°F (31.0°C) at Rome Ciampino, 87.3°F (30.7°C²) at Milan Linate, 86.4°F (30.2°C²) at Trapani Birgi, 84.2°F (29.0°C) at Venice Tessera and 61.2°F (16.2°C²) at Passo Rolle.

Read that list twice. Florence, inland and enclosed, runs hotter in July than western Sicily, and Milan runs hotter than Trapani. The heat that hurts in Italy is a continental and valley phenomenon, not a southern one.

Annual means: 14°C between an Alpine pass and Naples

Across the year the range is nearly 14°C wide: 3.2°C at Passo Rolle, 6,575 feet (2,004 m), against 17.1°C² at Naples Capodichino, with Trapani Birgi at 18.1°C² and Ustica at 18.0°C at the warm end. In January the spread runs from -3.9°C at Passo Rolle to 11.4°C² at Trapani.

Milan Linate averages 14.2°C² over the year, Venice Tessera 13.9°C², Florence Peretola 15.5°C², Rome Ciampino 15.8°C²: four cities within 2°C of each other, with very different summers.

In Rome, August beats July

Rome's warmest month is August, mean 77.7°F (25.4°C³) and mean daily maximum 88.9°F (31.6°C), a shade above July at 77.2°F (25.1°C). The difference is small, and it means the second half of August offers no relief that the calendar guarantees.

The stations are at airports, and the cities are hotter

Every figure above comes from an airport station on the edge of its city, which is how the WMO series is built: 84 Italian stations, 30 years, at least 24 valid years for a value to exist. Historic centers run hotter through the urban heat island, and none of this data quantifies that gap.

Palermo is missing from the list because it has no complete 1991-2020 series. Where a station lacks the valid years, the number does not exist and this site leaves the hole visible.

Where the water is not

Summer rainfall in central and southern Italy and the islands drops to a marked minimum, with July totals between 3 and 25 mm. Trapani Birgi records 488.9 mm² across the whole year and Ustica 525.7 mm², the two driest in this set; Rome Fiumicino 622.6 mm².

Northern Italy behaves differently. The Po valley has a double maximum, in autumn and in late spring, with no dry season at all, and the Alps take their heaviest rain in July and August.

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