Weather in Puerto Montt in September

Shoulder season. September sits in between. You will get good days and you will lose some. Highs sit at 12.7 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

September ranks 8 of 12 in Puerto Montt: past the worst of the year but short of February, which is the month to book if the dates are open.

This is persistent light rain rather than storms: 15 wet days but only 2 heavy ones. It rarely cancels anything outright, and it rarely fully clears either. A jacket beats an umbrella. Layers, and a genuinely waterproof outer — at 12.7 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

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 24.3 °C and the coldest night fell to 0.1 °C, and the wettest single day dropped 39 mm — roughly 43% of the month's rain in one day.

September is moderately variable: 31 mm in the driest year against 164 mm in the wettest, around an average of 91 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 2.9 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 87%, which at 12.7 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How September sits in the year

The month is on the way up: 1.9 °C warmer than August, and October adds another 1.6 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short. Rain has already shifted: 5 days fewer than August had.

Daylight in September

11.8 hours of daylight, gaining 1.4 hours across the month. That is between Puerto Montt's extremes of 15.1 and 9.2 hours, so days are long enough not to constrain the plan.

An inland climate

Despite being inland, the year stays fairly even: 15.9 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

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

September in Puerto Montt versus nearby

If Puerto Montt is one option among several, the nearby comparison is worth making. Santiago is a better bet in September — 10.6 °C warmer, 12 days less rain. Córdoba is a better bet in September — 13 °C warmer, 11 days less rain.

So: September is a compromise. February is 34 points better and is what Puerto Montt is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Puerto Montt

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