Weather in Cagliari in September

Prime time. September is about as good as Cagliari gets. Highs average 25.5 °C, lows 22.1 °C, and rain falls on 6 days — nothing in the month is working against you.

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

Rain falls on only 6 days, so an itinerary with no wet-weather fallback is a reasonable risk. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: it never really gets hot: not one day in an average September reaches 30 °C; the day barely swings — 3.5 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest September day reached 30.8 °C and the coldest night fell to 16.9 °C, and the wettest single day dropped 34 mm — roughly 89% of the month's rain in one day.

September is moderately variable: 4 mm in the driest year against 117 mm in the wettest, around an average of 38 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 14.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 72%.

How September sits in the year

The month is on the way down: 2.7 °C cooler than August, with October dropping another 2.9 °C. The first week and the last are not the same trip.

Daylight in September

12.5 hours of daylight, losing 1.3 hours across the month. That is between Cagliari's extremes of 14.9 and 9.4 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 24.3 °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 Cagliari versus nearby

If Cagliari is one option among several, the nearby comparison is worth making. Palermo is the weaker option in September — 2.9 °C warmer, 3 days more rain. Rome is the weaker option in September — 2.7 °C warmer, 3 days more rain.

So: September works, with June the better month by 8 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Cagliari

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