Weather in Salta in December

A hard month. December asks something of you. Go in knowing what. You should expect rain on 15 days of the month, which is more days wet than dry.

December ranks 12 of 12 — near the bottom of Salta's year. June is the month that works, and the swing between the two is 50 points, which is a different holiday rather than a slightly better one.

Rain on 15 days, 5 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 31.6 °C days and 19.1 °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: 6 days clear 35 °C, so a serious heatwave is normal rather than notable. Across the twenty years measured, the hottest December day reached 40.7 °C and the coldest night fell to 9.1 °C, and the wettest single day dropped 97 mm — roughly 69% of the month's rain in one day.

December is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest December on record still delivered 259 mm against 67 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 141 mm average is a reasonable planning figure, not a promise.

Wind is light at 10 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 69%.

How December sits in the year

Temperatures hold steady either side: 31.9 °C in November, 31.6 here, 30.7 in January. Nothing about the timing within the month matters much. Rain has already shifted: 6 days more than November had.

Daylight in December

December is at or near the longest days of Salta's year: 13.7 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: 21.9 °C between the year's warmest afternoons and coldest nights. At 1054 m the air is thin enough to matter — sun that burns faster than the temperature suggests, and nights that cool off quickly.

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 Salta versus nearby

If Salta is one option among several, the nearby comparison is worth making. San Miguel de Tucumán is close enough to be a coin toss — 2 °C warmer, 2 days less rain. Antofagasta is a better bet in December — 11.5 °C cooler, 15 days less rain.

So: December is a compromise. June is 50 points better and is what Salta 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 Salta

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