Climate averages 1991–2020
San Juan, Argentina weather
in December.
A hot, fairly dry month: the 2nd warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a hot month in San Juan, Argentina: daytime highs average 30.3°C and nights cool to about 17.7°C. By daytime temperature it is the 2nd warmest of the 12 months.
Expect about 22 mm of rain on roughly 3 days, which makes December a fairly dry month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 09 min on an average December day.
The nearest other city in this atlas is Rawson (5 km away). In December its highs average 29.8°C, about as warm as San Juan, Argentina, with 22 mm of rain.
Among the 67 cities listed in Argentina, San Juan, Argentina ranks joint 9th of 67 for the warmest December highs and joint 6th of 67 for the driest December (rainfall, lowest first). The mean December high of those 67 cities is 27.9°C; San Juan, Argentina is 2.5°C warmer than that mean.
From December to January, average highs rise by 0.6°C to 31.0°C, and monthly rainfall falls from 22 mm to 17 mm.
The annual picture
December in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San Juan, Argentina climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 31.0°C19.2°C | 19.2°C | 17 | 3.2 | 13.914 h |
| February | 29.7°C18.0°C | 18.0°C | 20 | 3.4 | 13.213 h |
| March | 27.2°C15.8°C | 15.8°C | 24 | 3.9 | 12.312 h |
| April | 23.2°C11.6°C | 11.6°C | 18 | 3.3 | 11.311 h |
| May | 19.6°C7.6°C | 7.6°C | 10 | 2.6 | 10.511 h |
| June | 17.4°C4.1°C | 4.1°C | 7.8 | 2.0 | 10.110 h |
| July | 16.4°C2.9°C | 2.9°C | 8.2 | 2.2 | 10.310 h |
| August | 19.4°C5.0°C | 5.0°C | 10 | 2.3 | 11.011 h |
| September | 21.8°C8.0°C | 8.0°C | 17 | 3.3 | 11.912 h |
| October | 25.1°C11.8°C | 11.8°C | 21 | 3.5 | 12.813 h |
| November | 28.0°C15.0°C | 15.0°C | 16 | 3.2 | 13.714 h |
| December, selected | 30.3°C17.7°C | 17.7°C | 22 | 3.3 | 14.214 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
December in nearby cities
- Rawson in DecemberArgentina · 5 kmHigh 29.8°C · Low 16.9°C · 22 mm rain
- Mendoza in DecemberArgentina · 153 kmHigh 27.6°C · Low 16.3°C · 48 mm rain
- San Martín in DecemberArgentina · 172 kmHigh 30.9°C · Low 18.8°C · 39 mm rain
- Colina in DecemberChile · 274 kmHigh 27.9°C · Low 16.3°C · 13 mm rain
- Ovalle in DecemberChile · 275 kmHigh 28.7°C · Low 15.6°C · 0.3 mm rain
- San Luis in DecemberArgentina · 284 kmHigh 28.9°C · Low 18.0°C · 101 mm rain
- Peñalolén in DecemberChile · 286 kmHigh 24.9°C · Low 13.6°C · 25 mm rain
- Quilicura in DecemberChile · 289 kmHigh 26.7°C · Low 14.8°C · 13 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for San Juan) is explained once on the San Juan, Argentina year overview and on the Sources, method and limits page.
Rawson lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.