Porto has a warm-summer Mediterranean climate (Köppen Csb) with strong Atlantic Ocean influence. Located at the mouth of the Douro River in northern Portugal, the city is notably cooler and wetter than Lisbon or the Algarve. Annual rainfall averages 1,250mm (49 inches), more than double Lisbon’s total, concentrated heavily between October and April. Summers are warm and dry with cooling Atlantic breezes. Winters are mild but very wet. The city is famous for its frequent morning fog (nevoeiro) that rolls in from the Atlantic, especially in autumn and winter, often burning off by midday.
Porto Monthly Temperature and Rainfall
| Month | Avg High (°C/°F) | Avg Low (°C/°F) | Rainfall (mm) | Rain Days | Humidity (%) | Sea Temp (°C/°F) |
|---|---|---|---|---|---|---|
| January | 14 / 57 | 5 / 42 | 158 | 17 | 81 | 14 / 57 |
| February | 15 / 59 | 6 / 43 | 122 | 14 | 77 | 14 / 57 |
| March | 17 / 63 | 8 / 46 | 96 | 13 | 73 | 14 / 57 |
| April | 18 / 65 | 9 / 48 | 118 | 13 | 73 | 15 / 59 |
| May | 20 / 69 | 12 / 53 | 90 | 11 | 72 | 16 / 61 |
| June | 24 / 75 | 15 / 58 | 46 | 7 | 72 | 18 / 64 |
| July | 25 / 78 | 16 / 60 | 20 | 4 | 71 | 18 / 65 |
| August | 25 / 78 | 16 / 60 | 27 | 4 | 70 | 19 / 66 |
| September | 24 / 75 | 14 / 58 | 65 | 8 | 73 | 18 / 65 |
| October | 21 / 69 | 12 / 53 | 145 | 14 | 77 | 17 / 63 |
| November | 17 / 62 | 8 / 47 | 156 | 15 | 80 | 16 / 61 |
| December | 14 / 58 | 6 / 43 | 178 | 16 | 82 | 15 / 59 |
Summer Weather in Porto (June to September)
Summer is the best season for Porto. June through September brings warm, dry days with July and August averaging 25°C (78°F) highs and 16°C (60°F) lows. July is the driest month at just 20mm over 4 rain days. August has 27mm over 4 days. Humidity is moderate at 70-73%. The Atlantic keeps temperatures lower than inland Iberia: Porto rarely exceeds 32°C (90°F), with cooling sea breezes in the afternoons.
Sea temperatures reach 18-19°C (64-66°F) in August-September, swimmable if brisk. The beaches at Foz do Douro and Matosinhos fill with locals on weekends. June has the São João festival, the city’s biggest annual celebration. September remains warm (24°C/75°F) but rain increases to 65mm over 8 days. Our Porto events and festivals guide covers the summer festival calendar.
Winter Weather in Porto (December to February)
Winters are mild by European standards but extremely wet. Daytime highs average 14-15°C (57-59°F) and lows drop to 5-6°C (42-43°F). December is the wettest month at 178mm over 16 rain days, January averages 158mm over 17 days. Rain is persistent drizzle rather than thunderstorms. The city gets 5-6 hours of daily sun in winter.
Snow is virtually unknown. The Douro Valley fog can linger until midday. The upside: Porto’s winter light, when the sun breaks through, is beautiful with low golden angles. Hotel prices are at their lowest and the port wine lodges in Vila Nova de Gaia are warm and welcoming.
Pack a waterproof jacket and waterproof shoes: the granite sidewalks become extremely slippery when wet. For seasonal planning, see our best time to visit Porto guide.
Spring and Autumn Weather in Porto
Spring (March-May) warms from 17°C (63°F) to 20°C (69°F) but remains wet: March 96mm, April 118mm, May 90mm, each with 11-13 rain days. May is the transition to summer and the first month with passable beach weather. Autumn (October-November) sees 21°C (69°F) in October cooling to 17°C (62°F) in November, with rain surging back (145mm and 156mm respectively).
October can deliver beautiful Indian summer weeks with clear skies and 22-24°C (72-75°F) days mixed with rainy spells. The Douro Valley vineyards put on autumn colors in October-November, making it an excellent time for wine tourism despite the rain risk. The things to do in Porto guide lists indoor attractions for rainy days.
