Weather in Zagreb in December
Croatia · 20-year averages, December
The month to avoid. Of the twelve, December is the one to avoid. Highs sit at 4.4 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.
December ranks 12 of 12 — near the bottom of Zagreb's year. September is the month that works, and the swing between the two is 48 points, which is a different holiday rather than a slightly better one.
Rain on 9 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 4.4 °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: 21 nights drop below freezing, so anything left outside stays frozen. Across the twenty years measured, the hottest December day reached 17.1 °C and the coldest night fell to -16 °C, and the wettest single day dropped 29 mm — roughly 46% of the month's rain in one day.
December is moderately variable: 4 mm in the driest year against 105 mm in the wettest, around an average of 63 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.
Wind is light at 6.7 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 92%, which at 4.4 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.
How December sits in the year
Temperatures hold steady either side: 10.4 °C in November, 4.4 here, 3.3 in January. Nothing about the timing within the month matters much.
Daylight in December
December sits at the dark end of Zagreb'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 — 32.2 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.
How busy it gets
Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.
Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.
December in Zagreb versus nearby
If Zagreb is one option among several, the nearby comparison is worth making. Graz is close enough to be a coin toss — within a degree on temperature, 1 day less rain. Trieste is a better bet in December — 5 °C warmer, 1 day more rain.
So: December is a compromise. September is 48 points better and is what Zagreb 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 Zagreb
| Month | High °C | Low °C | Rain days | Rain mm | Humidity % | Daylight h | Score |
|---|---|---|---|---|---|---|---|
| January | 3.3 | -3.2 | 8 | 52 | 92 | 9 | 30 |
| February | 5.7 | -2.1 | 9 | 60 | 89 | 10.3 | 34 |
| March | 11.3 | 1.2 | 9 | 59 | 83 | 11.8 | 55 |
| April | 17 | 6 | 10 | 62 | 77 | 13.5 | 72 |
| May | 21.4 | 10.5 | 13 | 92 | 74 | 14.9 | 75 |
| June | 26 | 14.9 | 13 | 86 | 69 | 15.7 | 76 |
| July | 29 | 17 | 12 | 82 | 63 | 15.4 | 68 |
| August | 29 | 16.8 | 10 | 83 | 62 | 14.2 | 71 |
| September | 22.9 | 11.8 | 11 | 107 | 71 | 12.6 | 78 |
| October | 17.2 | 6.9 | 9 | 83 | 82 | 11 | 72 |
| November | 10.4 | 2.9 | 9 | 79 | 90 | 9.5 | 51 |
| December | 4.4 | -1.7 | 9 | 63 | 92 | 8.7 | 30 |
See all twelve months in Zagreb, or where else to go in December.
Planning the rest of the trip
- Flight time to Zagreb how long you are actually in the air
- Zagreb time zone and the difference from home
- Days until your trip count down to the departure date