Santiago weather in September
In September, Santiago has an average high of 23 °C73 °F and an average low of 9 °C48 °F, with about 15 mm0.6 in of precipitation. It is the 9th warmest month of the year and ranks 5th for precipitation.
How September compares with other months
Compared with August, September is 2.1 °C3.8 °F warmer on average and drier by 25 mm1.0 in. Compared with October, September is 2.7 °C4.9 °F cooler on average. Daylight lasts about 11.9 hours around the middle of the month. Average relative humidity is 49% and the average cloud amount 68%.
Is September a good time to visit Santiago?
Yes — September is one of the most comfortable months to visit Santiago by our comfort score, which favours average highs of 21–28 °C, lows above 5 °C, little rain and moderate humidity.
What to wear in September
For Santiago in September, pack light layers — T-shirts plus a light sweater or jacket and an extra layer for the cooler mornings and evenings.
September in nearby places
| Place | High °C°F | Low °C°F | Precip. mmin |
|---|---|---|---|
| Santiago | 2373 | 948 | 150.6 |
| Colina | 2374 | 1050 | 130.5 |
| Rancagua | 2272 | 948 | 180.7 |
| Viña del Mar | 2169 | 1049 | 150.6 |
| Valparaíso | 1457 | 1151 | 130.5 |
| Curicó | 2068 | 745 | 230.9 |
| Mendoza | 2271 | 643 | 80.3 |
| Talca | 1864 | 542 | 361.4 |
| San Rafael | 2169 | 642 | 210.8 |
Nearby places that are more than 1 °C1.8 °F cooler: Valparaíso, Curicó, Mendoza and Talca.
Other months in Santiago
- January34 °C92 °F / 18 °C65 °F
- February32 °C90 °F / 18 °C64 °F
- March31 °C87 °F / 16 °C61 °F
- April27 °C80 °F / 13 °C56 °F
- May23 °C73 °F / 10 °C50 °F
- June19 °C66 °F / 7 °C45 °F
- July18 °C65 °F / 6 °C43 °F
- August20 °C68 °F / 7 °C45 °F
- September23 °C73 °F / 9 °C48 °F
- October26 °C79 °F / 11 °C52 °F
- November30 °C86 °F / 14 °C57 °F
- December32 °C90 °F / 16 °C62 °F
Frequently asked questions
How warm is Santiago in September?
In September the average high in Santiago is 23 °C (73 °F) and the average low is 9 °C (48 °F).
Does it rain a lot in Santiago in September?
On average about 15 mm (0.6 in) of precipitation falls in September; it ranks 5th of the 12 months.
Is September the warmest month in Santiago?
No. The warmest month in Santiago is January, with an average high of 34 °C (92 °F). The coldest month is July, with an average low of 6 °C (43 °F).
How long is the day in Santiago in September?
In the middle of September the day in Santiago lasts about 11.9 hours from sunrise to sunset. The value is calculated from the position of the city and the sun.
How humid is Santiago in September?
The average relative humidity in September is about 49%. This is a long-term average for the whole day.
How cloudy is Santiago in September?
On average about 68% of the sky is covered by cloud in September. This is the mean cloud amount from satellite data, not the number of sunny days.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 1,154 m, while Santiago lies at about 556 m. Temperatures on this page were therefore adjusted by +3.9 °C7 °F using the standard lapse rate of 6.5 °C per 1,000 m.