Climate averages 1991–2020
San Luis weather
in September.
A mild, fairly dry month: the 8th warmest and the 5th driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in San Luis: daytime highs average 21.3°C and nights cool to about 9.4°C. By daytime temperature it is the 8th warmest of the 12 months.
Expect about 30 mm of rain on roughly 5 days, which makes September a fairly dry month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 52 min on an average September day.
The nearest other city in this atlas is Villa Mercedes, Argentina (91 km away). In September its highs average 20.9°C, about as warm as San Luis, with 36 mm of rain.
Among the 67 cities listed in Argentina, San Luis ranks joint 16th of 67 for the warmest September highs and 14th of 67 for the driest September (rainfall, lowest first). The mean September high of those 67 cities is 19.4°C; San Luis is 1.9°C warmer than that mean.
From September to October, average highs rise by 2.6°C to 23.9°C, and monthly rainfall rises from 30 mm to 66 mm.
The annual picture
September 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, selected | 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 | 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
September in nearby cities
- Villa Mercedes, Argentina in SeptemberArgentina · 91 kmHigh 20.9°C · Low 8.9°C · 36 mm rain
- Río Cuarto in SeptemberArgentina · 184 kmHigh 20.3°C · Low 9.3°C · 39 mm rain
- San Martín in SeptemberArgentina · 201 kmHigh 21.1°C · Low 8.5°C · 11 mm rain
- San Rafael in SeptemberArgentina · 237 kmHigh 19.4°C · Low 6.3°C · 28 mm rain
- Mendoza in SeptemberArgentina · 239 kmHigh 18.3°C · Low 6.1°C · 28 mm rain
- Rawson in SeptemberArgentina · 282 kmHigh 21.5°C · Low 7.3°C · 17 mm rain
- San Juan, Argentina in SeptemberArgentina · 284 kmHigh 21.8°C · Low 8.0°C · 17 mm rain
- Córdoba in SeptemberArgentina · 290 kmHigh 21.3°C · Low 9.2°C · 37 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.