Weather in Cagliari in December

A good month. December is a solid month to be in Cagliari. Highs average 15.4 °C, lows 12.7 °C, and rain falls on 10 days — nothing in the month is working against you.

December ranks 10 of 12 — near the bottom of Cagliari's year. June is the month that works, and the swing between the two is 33 points, which is a different holiday rather than a slightly better one. Worth keeping in perspective: December is the weakest month of Cagliari's year and it is still a perfectly good one. The downside here is small.

Rain on 10 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 15.4 °C days and 12.7 °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: the day barely swings — 2.7 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 19.5 °C and the coldest night fell to 6.5 °C, and the wettest single day dropped 52 mm — roughly 78% of the month's rain in one day.

December is moderately variable: 9 mm in the driest year against 157 mm in the wettest, around an average of 67 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.

Wind sits around 18.8 km/h — a steady breeze rather than a nuisance, and welcome on the warmer days, and humidity runs at 77%, high enough to notice on the warm days without dominating them.

How December sits in the year

Temperatures hold steady either side: 18.5 °C in November, 15.4 here, 14.1 in January. Nothing about the timing within the month matters much.

Daylight in December

December sits at the dark end of Cagliari's year — 9.4 hours of daylight against 14.9 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

Sea temperature

The sea sits at about 16.2 °C in December — cold — a quick dip rather than a swim, and a wetsuit if you are in for longer. The sea peaks at 25.7 °C in August and bottoms out at 14.1 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

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

December in Cagliari versus nearby

If Cagliari is one option among several, the nearby comparison is worth making. Palermo is close enough to be a coin toss — within a degree on temperature, 3 days more rain. Rome is close enough to be a coin toss — within a degree on temperature, 1 day more rain.

So: December is a compromise. June is 31 points better and is what Cagliari is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Cagliari

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