Weather in Aveiro in September

Prime time. September is about as good as Aveiro gets. Highs average 25.7 °C, lows 15.9 °C, and rain falls on 6 days — nothing in the month is working against you.

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

Rain falls on only 6 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 34.4 °C and the coldest night fell to 10.8 °C, and the wettest single day dropped 49 mm — roughly 104% of the month's rain in one day.

This is the volatile part. September rainfall has ranged from 4 mm to 154 mm across the twenty years measured — a 150 mm spread around an average of 47 mm. The average is real but almost no individual September looks like it, so treat the figure as the middle of a wide range rather than a forecast.

Wind is light at 4.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 71%.

How September sits in the year

Temperatures hold steady either side: 26.8 °C in August, 25.7 here, 21.9 in October. Nothing about the timing within the month matters much. Rain is the thing that moves: October brings 7 days more of it, so the earlier half of a flexible trip is the safer half.

Daylight in September

12.5 hours of daylight, losing 1.3 hours across the month. That is between Aveiro's extremes of 15.1 and 9.3 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 18.5 °C in September — swimmable, but it takes a moment to commit. This is the warmest the water gets all year.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

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

September in Aveiro versus nearby

If Aveiro is one option among several, the nearby comparison is worth making. Leiria is close enough to be a coin toss — 2.6 °C warmer, 1 day less rain. Braga is close enough to be a coin toss — 3.1 °C warmer, the same number of rain days.

So: September works, with July the better month by 9 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Aveiro

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