Weather in Buenos Aires in December

Prime time. December is about as good as Buenos Aires gets. Highs average 26 °C, lows 19.7 °C, and rain falls on 8 days — nothing in the month is working against you.

Buenos Aires barely has seasons. December scores 83 out of 100 against a best of 83 in April — a gap small enough that the month you choose matters far less here than the week you choose.

Rain on 8 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest December day reached 34.4 °C and the coldest night fell to 12.3 °C, and the wettest single day dropped 68 mm — roughly 72% of the month's rain in one day.

December is moderately variable: 21 mm in the driest year against 231 mm in the wettest, around an average of 94 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.

Wind sits around 17 km/h — a steady breeze rather than a nuisance, and welcome on the warmer days, and humidity is unremarkable at 68%.

How December sits in the year

The month is on the way up: 2.6 °C warmer than November, and January adds another 1.6 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in December

December is at or near the longest days of Buenos Aires's year: 14.5 hours of daylight, holding steady all month. Evenings are the real gain — dinner outdoors still happens in full light.

An inland climate

Despite being inland, the year stays fairly even: 18.9 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead. If the dates are flexible, May is the trade worth considering — 6 points weaker on weather, and materially quieter.

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

December in Buenos Aires versus nearby

If Buenos Aires is one option among several, the nearby comparison is worth making. Rosario is the weaker option in December — 5.5 °C warmer, 3 days more rain. Mar del Plata is close enough to be a coin toss — 3.2 °C cooler, 3 days more rain.

So: December is effectively as good as it gets here — 0 points behind April, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Buenos Aires

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