Climate averages 1991–2020
San Juan, Argentina weather
in September.
A mild, fairly dry month: the 8th warmest and the joint 6th 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 Juan, Argentina: daytime highs average 21.8°C and nights cool to about 8.0°C. By daytime temperature it is the 8th warmest of the 12 months.
Expect about 17 mm of rain on roughly 3 days, which makes September a fairly dry month (the joint 6th 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 Rawson (5 km away). In September its highs average 21.5°C, about as warm as San Juan, Argentina, with 17 mm of rain.
Among the 67 cities listed in Argentina, San Juan, Argentina ranks joint 12th of 67 for the warmest September highs and joint 3rd of 67 for the driest September (rainfall, lowest first). The mean September high of those 67 cities is 19.4°C; San Juan, Argentina is 2.4°C warmer than that mean.
From September to October, average highs rise by 3.3°C to 25.1°C, and monthly rainfall rises from 17 mm to 21 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 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, selected | 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 | 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
September in nearby cities
- Rawson in SeptemberArgentina · 5 kmHigh 21.5°C · Low 7.3°C · 17 mm rain
- Mendoza in SeptemberArgentina · 153 kmHigh 18.3°C · Low 6.1°C · 28 mm rain
- San Martín in SeptemberArgentina · 172 kmHigh 21.1°C · Low 8.5°C · 11 mm rain
- Colina in SeptemberChile · 274 kmHigh 18.8°C · Low 7.8°C · 77 mm rain
- Ovalle in SeptemberChile · 275 kmHigh 22.8°C · Low 10.3°C · 7.9 mm rain
- San Luis in SeptemberArgentina · 284 kmHigh 21.3°C · Low 9.4°C · 30 mm rain
- Peñalolén in SeptemberChile · 286 kmHigh 16.3°C · Low 4.9°C · 72 mm rain
- Quilicura in SeptemberChile · 289 kmHigh 18.0°C · Low 6.4°C · 77 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.