Weather in Arica in September

A good month. September is a solid month to be in Arica. Highs average 33.1 °C, lows 20.2 °C, and rain falls on 0 days — nothing in the month is working against you.

September ranks 4 of 12 in Arica: past the worst of the year but short of June, which is the month to book if the dates are open.

Rain is not a factor worth planning around this month. Pack for 33.1 °C days and 20.2 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 5 days clear 35 °C, so a serious heatwave is normal rather than notable. Across the twenty years measured, the hottest September day reached 38.9 °C and the coldest night fell to 15.9 °C.

September is dependably dry, and that reliability is the point: across the twenty years measured, the wettest September on record still only managed 9 mm, and the driest managed 0 mm. There is no meaningful variability to plan around, which makes this one of the few months anywhere that you can build a fixed outdoor itinerary against without a fallback. The wettest single day in twenty years of Septembers brought 3 mm. Rain simply is not the variable that decides this trip — heat, crowds and cost are.

Wind is light at 7.4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 42%.

How September sits in the year

Temperatures hold steady either side: 32.8 °C in August, 33.1 here, 33.3 in October. Nothing about the timing within the month matters much.

Daylight in September

12 hours of daylight, gaining 0.5 hours across the month. That is between Arica's extremes of 13.2 and 11 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 17.2 °C in September — cold — a quick dip rather than a swim, and a wetsuit if you are in for longer. The sea peaks at 24.3 °C in February and bottoms out at 17.1 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

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

September in Arica versus nearby

If Arica is one option among several, the nearby comparison is worth making. Arequipa is a better bet in September — 7 °C cooler, 1 day more rain. Antofagasta is a better bet in September — 16.9 °C cooler, the same number of rain days.

So: September is effectively as good as it gets here — 3 points behind June, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Arica

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