Weather in Trieste in December

A hard month. December is a hard month in Trieste, and worth planning around. Highs sit at 9.4 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

December ranks 10 of 12 — near the bottom of Trieste's year. June is the month that works, and the swing between the two is 34 points, which is a different holiday rather than a slightly better one.

Rain on 10 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 9.4 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 3 nights fall below freezing; the day barely swings — 5 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 16.3 °C and the coldest night fell to -5 °C, and the wettest single day dropped 55 mm — roughly 57% of the month's rain in one day.

December is moderately variable: 1 mm in the driest year against 235 mm in the wettest, around an average of 96 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.

Wind is light at 8.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 82%, which at 9.4 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How December sits in the year

The month is on the way down: 4.5 °C cooler than November, with January dropping another 1.6 °C. The first week and the last are not the same trip.

Daylight in December

December sits at the dark end of Trieste's year — 8.7 hours of daylight against 15.7 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

With no coast nearby, the year swings a fair way — 25.7 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

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 Trieste versus nearby

If Trieste is one option among several, the nearby comparison is worth making. Villach is the weaker option in December — 4.5 °C cooler, 1 day less rain. Padua is close enough to be a coin toss — within a degree on temperature, 2 days less rain.

So: December is a compromise. June is 32 points better and is what Trieste 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 Trieste

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