Climate averages 1991–2020
San Luis weather
in December.
A hot, wet 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 Luis: daytime highs average 28.9°C and nights cool to about 18.0°C. By daytime temperature it is the 2nd warmest of the 12 months.
Expect about 101 mm of rain on roughly 13 days, which makes December a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 18 min on an average December day.
The nearest other city in this atlas is Villa Mercedes, Argentina (91 km away). In December its highs average 28.8°C, about as warm as San Luis, with 96 mm of rain.
Among the 67 cities listed in Argentina, San Luis ranks joint 23rd of 67 for the warmest December highs and 41st of 67 for the driest December (rainfall, lowest first). The mean December high of those 67 cities is 27.9°C; San Luis is 1.0°C warmer than that mean.
From December to January, average highs rise by 0.8°C to 29.7°C, and monthly rainfall rises from 101 mm to 107 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 Luis climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 29.7°C19.2°C | 19.2°C | 107 | 13.2 | 14.114 h |
| February | 28.2°C18.1°C | 18.1°C | 82 | 10.9 | 13.313 h |
| March | 26.0°C16.4°C | 16.4°C | 80 | 10.0 | 12.312 h |
| April | 21.8°C12.5°C | 12.5°C | 53 | 7.0 | 11.311 h |
| May | 18.6°C9.1°C | 9.1°C | 25 | 4.2 | 10.410 h |
| June | 16.4°C6.2°C | 6.2°C | 8.3 | 1.9 | 10.010 h |
| July | 15.9°C5.0°C | 5.0°C | 9.1 | 2.1 | 10.210 h |
| August | 18.9°C7.0°C | 7.0°C | 15 | 2.6 | 10.911 h |
| September | 21.3°C9.4°C | 9.4°C | 30 | 4.6 | 11.912 h |
| October | 23.9°C12.5°C | 12.5°C | 66 | 8.7 | 12.913 h |
| November | 26.6°C15.5°C | 15.5°C | 89 | 11.7 | 13.814 h |
| December, selected | 28.9°C18.0°C | 18.0°C | 101 | 13.1 | 14.314 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
- Villa Mercedes, Argentina in DecemberArgentina · 91 kmHigh 28.8°C · Low 17.6°C · 96 mm rain
- Río Cuarto in DecemberArgentina · 184 kmHigh 28.3°C · Low 17.9°C · 107 mm rain
- San Martín in DecemberArgentina · 201 kmHigh 30.9°C · Low 18.8°C · 39 mm rain
- San Rafael in DecemberArgentina · 237 kmHigh 29.3°C · Low 16.7°C · 53 mm rain
- Mendoza in DecemberArgentina · 239 kmHigh 27.6°C · Low 16.3°C · 48 mm rain
- Rawson in DecemberArgentina · 282 kmHigh 29.8°C · Low 16.9°C · 22 mm rain
- San Juan, Argentina in DecemberArgentina · 284 kmHigh 30.3°C · Low 17.7°C · 22 mm rain
- Córdoba in DecemberArgentina · 290 kmHigh 28.4°C · Low 17.7°C · 131 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 Luis) is explained once on the San Luis year overview and on the Sources, method and limits page.