Weather in Santiago in September

Prime time. If you get to pick your dates, September is the one. Highs average 23.3 °C, lows 9.4 °C, and rain falls on 3 days — nothing in the month is working against you.

September is the highest-scoring month of the twelve. The nearest rival is October, and the month at the other end of the year is January.

Rain falls on only 3 days, so an itinerary with no wet-weather fallback is a reasonable risk. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest September day reached 35.7 °C and the coldest night fell to 1.2 °C.

September is moderately variable: 1 mm in the driest year against 40 mm in the wettest, around an average of 15 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 5.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 49%.

How September sits in the year

The month is on the way up: 2.3 °C warmer than August, and October adds another 3.1 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in September

11.8 hours of daylight, gaining 1 hours across the month. That is between Santiago's extremes of 14.3 and 9.9 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 26.3 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead. If the dates are flexible, November is the trade worth considering — 12 points weaker on weather, and materially quieter.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Santiago versus nearby

If Santiago is one option among several, the nearby comparison is worth making. Córdoba is close enough to be a coin toss — 2.4 °C warmer, 1 day more rain. San Miguel de Tucumán is the weaker option in September — 6 °C warmer, 1 day less rain.

So: September is the answer for Santiago. If it is booked out or priced out, October is the next best thing at 0 points behind, and January is the month to keep off the shortlist.

Every month in Santiago

See all twelve months in Santiago, or where else to go in September.