Porto weather by monthtemperature, rain and sea

Short answer: Porto is mild and wet. Highs run from 14 °C in January to 25 °C in August; from October to April expect 10 to 13 rain days a month, while July and August get about 3. The Atlantic stays cool, between 14 and 18 °C. Which months suit which trip: best time to visit Porto.

Month	High °C	Low °C	Rain mm	Rain days	Sea °C
January	14.0	6.4	151.0	12.8	14.3
February	15.0	6.8	97.8	10.0	13.8
March	17.0	8.8	101.1	9.9	13.8
April	18.1	10.1	95.5	10.4	14.9
May	20.3	12.3	85.6	8.9	16.2
June	22.7	14.5	33.7	4.9	17.2
July	24.3	15.5	16.6	3.1	17.3
August	24.8	15.7	29.3	3.2	17.9
September	23.5	14.8	68.2	5.8	18.3
October	20.7	12.9	148.9	11.1	17.8
November	16.8	9.4	165.9	13.0	16.8
December	14.7	7.6	153.3	12.4	15.4

High, low, rain and rain days (≥ 1 mm): IPMA climate normal 1991–2020 for Porto / Pedras Rubras, the airport station 11 km north of the centre at 67.7 m. Annual total 1,146.9 mm over 105.4 rain days; 46.9 days a year reach 25 °C and 13.0 days reach 30 °C. Sea: seatemperature.org monthly averages for Porto (modelled).

Heat, frost and extremes

• Days with a maximum of 30 °C or more: 2.5 in June, 3.1 in July, 3.5 in August, 2.2 in September. [IPMA]
• Frost is rare: 1.4 days a year below 0 °C, mostly in January. [IPMA]
• The station’s record high in the period is 38.6 °C (7 August 2016). [IPMA]

How to read the year

November to February. The wet season. Highs of 14 to 17 °C and nights of 6 to 9 °C, with 10 to 13 rain days a month and 150 to 166 mm of rain in November, December and January. From November to January about 5 to 6 days a month bring 10 mm or more. [IPMA] For a winter month in a rented flat, heating and damp matter more than the averages: ask what the flat has.

March to May. Highs climb from 17 to 20 °C, but rain stays frequent: 9 to 10 rain days a month and 85 to 101 mm. [IPMA] Pack for showers even in May.

June to September. The dry season. Highs of 22.7 to 24.8 °C, nights of 14.5 to 15.7 °C, and 3 to 6 rain days a month; July has 16.6 mm. Only 2 to 3.5 days a month reach 30 °C. [IPMA] The sea peaks at about 18 °C in September (seatemperature.org, modelled). Beaches are lifeguarded from mid-June to mid-September (13 June to 13 September in 2026). [Portaria 204-A/2026]

October. The switch: still 20.7 °C by day, but 148.9 mm of rain over about 11 days, almost as wet as winter. [IPMA] What autumn means for a trip: Porto in autumn.

What the weather means for a work month or a family stay

What the numbers say; for events, prices and crowds see best time to visit Porto.

• For beach days with children: mid-June to mid-September: June to September are the only months with fewer than 6 rain days, and lifeguards work only in the bathing season (13 June to 13 September in 2026). July and August are the driest. [IPMA; Portaria 204-A/2026] Which beach for which day: Porto’s best beaches.
• For a work month with fewer crowds: May and late September to early October in the averages: highs of 20 to 23 °C, but May still has about 9 rain days and October 11. [IPMA] Crowd levels are not in the data; that is our assumption.
• Winter: mild by northern European standards (14 °C highs in January), but wet; for winter sun the Algarve is drier. Lagos averages 59 mm of rain in January against Porto’s 151 mm (see Lagos weather by month).

Porto in winter

Short answer: mild and wet. From December to February, days reach 14 to 15 °C and nights 6 to 8 °C, with 10 to 13 rain days a month; frost is rare (1.4 days a year). [IPMA] The sea is about 14 to 15 °C (seatemperature.org, modelled), and there are no lifeguards outside the bathing season.

• What to do: the indoor half of Porto works in any weather: the port cellars in Gaia, Livraria Lello, Clérigos Tower and the Bolhão market. See things to do in Porto, with a section on Christmas.
• Christmas and New Year: the city lights ran from 29 November 2025 (switched on at 18:00) to 6 January 2026, from 17:30 each evening after that, with a tree on the Avenida dos Aliados. [Ágora Porto] The market, New Year’s Eve, closures and holiday transport: Porto in December.
• With children: keep a rainy-day list ready: the aquarium, the planetarium and the biodiversity gallery are in Porto with kids.
• For a work month: winter is quieter and rents are not peak-season (our assumption, not sourced), but ask whether the flat is heated and dry; many older Porto flats are not built for wet winters (also our assumption).

Aveiro and the coast south of Porto

Aveiro / Universidade, 70 km south on the coast, is slightly milder and drier: highs of 14.6 °C in January and 24.5 °C in August, 975.5 mm of rain a year over 97 days against Porto’s 1,146.9 mm over 105. [IPMA] For trips there see Aveiro and Costa Nova from Porto.

The Douro valley is different

Inland, summers are much hotter. Vila Real (561 m, above the valley) averages a 29.0 °C maximum in August against 24.8 °C in Porto, with colder winters (9.9 °C maximum in January). The valley floor at Pinhão and Régua has no IPMA normal in this set. See the Douro valley.