Weather in Rome in September

A good month. September works. It is not the peak, but nothing about it fights you. Highs average 28.2 °C, lows 17.8 °C, and rain falls on 9 days — nothing in the month is working against you.

September ranks 5 of 12 in Rome: past the worst of the year but short of April, which is the month to book if the dates are open.

Rain on 9 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 28.2 °C days and 17.8 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 9 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest September day reached 37.7 °C and the coldest night fell to 9 °C, and the wettest single day dropped 55 mm — roughly 79% of the month's rain in one day.

September is moderately variable: 27 mm in the driest year against 126 mm in the wettest, around an average of 70 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 7.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 64%.

How September sits in the year

The month is on the way down: 5.3 °C cooler than August, with October dropping another 4.6 °C. The first week and the last are not the same trip. Rain has already shifted: 5 days more than August had.

Daylight in September

12.6 hours of daylight, losing 1.4 hours across the month. That is between Rome's extremes of 15.2 and 9.2 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 24.2 °C in September — warm enough to stay in as long as you like. This is the warmest the water gets all year.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Rome versus nearby

If Rome is one option among several, the nearby comparison is worth making. Naples is close enough to be a coin toss — within a degree on temperature, 1 day more rain. Positano is close enough to be a coin toss — 3.8 °C cooler, 2 days more rain.

So: September is effectively as good as it gets here — 6 points behind April, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Rome

See all twelve months in Rome, or where else to go in September.