Italy Weather by Month: 19 Freezing January Nights in Milan, 3 in Rome

Not Naples in the south, and not Venice near the Alps. It's Milan, with 18.8 sub-zero January nights on average — six times Rome's 3.2 — and a 7.7°C daytime high, nearly 5 degrees below Rome's 12.5°C. Milan sits in the Po Valley, a basin ringed by the Alps and Apennines where cold air pools in winter and thick fog can linger for days.

Summer flips it. Inland Rome and Florence are hottest, with 12–16 days above 33°C a month in July and August, while Venice, sitting on its lagoon, sees about two. In long, narrow Italy, distance from the sea and basin geography matter more than latitude.

Rome's July brings four rainy days and 19 mm of rain: clear, hot day after day. Enter shadeless sites like the Colosseum, the Forum and the Vatican gardens at opening time, and switch to museums from 1 to 4 p.m. Rome's nasoni (street fountains) will refill your bottle anywhere.

Italian rain runs opposite to Seoul's. Rome goes from 19 mm in July to 148 mm in November, 7.8 times as much. So autumn is golden until October, while November means carrying an umbrella. Marble floors and cobbles get slick in the wet; wear rubber soles.

From late autumn into winter, Venice gets acqua alta — high tides that push seawater into the city, mostly between October and January, flooding low spots like St Mark's Square first. Since 2020 the MOSE mobile barriers at the lagoon inlets have sharply cut flooding, but tides below the barrier-raising threshold still wet the square. Ask your hotel whether they lend boots.

Clothing advice is for Rome and Florence; go one step warmer in Milan and Venice in winter.

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Italy's best weather isn't in the July–August rush but in the two months either side of it.

• Period and source: daily values from Open-Meteo's historical weather data (ERA5 reanalysis), 2016–2025, averaged by month at each city-centre coordinate.
• Versus official normals: reanalysis temperatures usually land within 1–2°C of station normals, but downpours get smoothed out, so monthly rain totals come out lower and rainy-day counts slightly higher.
• Rainy day: at least 1 mm of precipitation. Reanalysis picks up even light showers, so counts run high — especially in the tropics, where monthly millimetres are the better guide. Most tropical rain is an hour or two of downpour, not a washed-out day.
• Best months: a first pass from temperature, rainy days and humidity, then adjusted for seasonal factors such as Ferragosto, acqua alta and the Amalfi off-season. It is a judgement call.