Porto (Oporto) weather in August
August in Porto: warm, dry, with clean air — one of the best months to visit.
Updated September 2026 · climate normals from ERA5 reanalysis
#1 of 12 months in Porto · #19 of 1413 destinations to visit in August · comfort 95/100 (tier S)
- Days
- 25°C
- Nights
- 15°C
- Wet days
- 2
- Sun
- 12.3 h
- Humidity
- 73%
- Daylight
- 14 h

Traveller notes on Porto in August
Regulars make two comparisons that decide the month. Against Lisbon: Porto is cooler and wetter, high seventies here against low eighties there - our row's 24.9C is that figure exactly - which in an August heatwave is the advantage. And against its own year: the city is not quite on the coast, its residents leave on holiday, and the crowds go to the beach towns, so August can be quieter here than other months even while the coast fills. The queues that remain are at the famous bookshop and the clock tower. The sea is Atlantic-cold at 16.2C. Rain is almost absent, 11mm across 2.2 days. The record: 15.3C nights, 12.3 hours of sun and AQI 41.
Other months in Porto
Regulars are specific that this month runs genuinely warm by Portuguese standards, a real step up from the cooler spring months just prior, even as rain stays a realistic possibility rather than a rare event. Our row backs that mild, still-showery read, 20.7C over 12.3C nights, with 79.6mm of rain across 9.7 days and humidity at 77 percent. Regulars are consistent this remains a comfortable month for walking the Ribeira and crossing the Dom Luis bridge without summer's crowds or heat, a light layer for cooler mornings and evenings the standard advice. The sea sits at a cold 15.3C, still too cool for most for a proper swim this early. The record: 11.9 hours of sun, a 17.4 kph wind and AQI 45.
June here is the month the board discusses one date. Sao Joao runs through the night of the 23rd into the 24th: the hotels sell out, the streets stay full until dawn, and the customs are specific - sardines and caldo verde eaten outdoors, paper balloons sent up over the city, fireworks by the river at midnight, and everybody hitting everybody else with squeaky plastic hammers, which is affection rather than assault. Their weather summary, about 23C by day and 14C at night, is almost exactly our row at 22.3C over 14.3C, so this is a mild month rather than a hot one - 55.7mm of rain across 8.4 days, a steady 16.8 kph off the Atlantic, and a sea still at 18.3C. The record: humidity 79 percent, 12.7 hours of sun and AQI 47.
Forum posters call March a genuinely lovely month to visit despite the rain risk - days are getting longer, spring blooms are starting, and a great sunny weekend is entirely possible alongside the more typical grey, foggy stretches. Porto is consistently described as rainier and foggier than Lisbon and the south, so the odds of a wet day are real, but posters are clear that a full week of solid rain is uncommon anywhere in Portugal, even in the north. Nearly everything touristy stays open year-round except the longer river cruises, so the advice is simply to have an indoor plan B rather than avoid the month.
Forum regulars call January Porto's coldest and rainiest month: daytime typically 10-15C, dropping to 5-6C at night, with rain on about 16 days of the month and occasional frost. One blunt assessment: over a 4-5 day visit there's a real chance you never see the sun. Still, nobody calls it a bad time to go - posters consistently say Porto and northern Portugal reward a visit any time of year if you're there for the architecture, history, food and culture rather than beach weather, and coming from a properly cold climate, at least there's no ice to worry about. The practical tip repeated most: book accommodation with real central heating, since night temperatures down to 4-5C catch people off guard indoors.
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Porto climate normals — August
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Porto in August
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
BusySummer holidays in Portugal, school holidays in 7 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Porto's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Best weatherPorto's weather peaks July–September, best around August.
Best weatherFair weatherToughest weather
What's on in Porto in August
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Season
The nortada
15 Jun – 15 Sep · usuallyWind seasonRiskThe Atlantic north wind gets up most summer afternoons, which is why Foz and Matosinhos feel ten degrees colder than the Ribeira and why the surf schools are where they are.
Nearby, and something's on
Within 300 km of Porto — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Porto?
Porto in August — FAQ
- Is August a good time to visit Porto?
- August in Porto: warm, dry, with clean air — one of the best months to visit. It ranks #1 of 12 months for Porto on SeasonMap's comfort score (95/100).
- What is the weather like in Porto in August?
- In August, Porto averages a daily high of 24.9°C and a low of 15.3°C, with about 11 mm of rain over roughly 2.2 rainy days.
- What is the air quality in Porto in August?
- Porto has a mean US Air Quality Index of about 41 in August.
Within 300 km: Ericeira's Festas da Senhora da Boa Viagem around 5–18 Aug, and Cascais' Festas do Mar on 20–30 Aug.