Weather in Porto in December

How December compares

December is the 11th warmest month of the year in Porto and ranks 95th of 134 destinations we compare for December - see where else is hot in December. Within Portugal it is 13th of 13 (Portugal in December). Against London's average high of 7.7°C in December, Porto is 5.9°C warmer by day and 4.8°C warmer at night.

Daytime and night-time in December

The typical December day in Porto peaks at 13.6°C, but that is an average: the warmest 10% of days reach 16.0°C or more. Days over 25°C are rare. Nights average 7.5°C; one night in ten drops to 3.4°C or lower, so pack a layer for evenings - it is genuinely cool after dark. Between 1991 and 2020 the hottest December day here reached 19.9°C (2019-12-25) and the coldest night -0.7°C (2001-12-25).

Rain in December

Wet (more than 8 rainy days): about 13 days with 1 mm or more, 170 mm in total. Year to year it varies a lot - the wettest December was 2000 with 534 mm, the driest 2001 with 20 mm. Humidity averages 83%.

Sea temperature in December

The sea averages 14.1°C - too cold for most (under 18°c). Depending on the year it ranges from 13.3°C to 15.1°C. For the warmest sea here, come in September (17.5°C).

Sunshine and daylight

Around 3.4 hours of sunshine a day (estimated from cloud cover), 9.0 hours of daylight: the sun rises about 07:53 and sets about 17:06 local time in mid-December. Average cloud cover is 62%.

Is December a good time to visit Porto?

December is not the strongest month here: cool days and frequent rain. The best months for Porto on our scoring are July, August, September; months averaging 25°C or more: Jul, Aug.

Rain and short days shape your plans

Rain is the main catch rather than severe daytime cold. December brings 170 mm of rainfall, so waterproof outerwear and shoes that cope with wet streets are more useful than packing only for the average temperature. There are about 3.4 hours of sunshine within 9 hours of daylight: some brighter weather is part of the picture, but this is not a dependable sunny break. Keep outdoor plans flexible and use dry spells rather than committing every day to being outside. With limited daylight, it makes sense to put longer walks earlier in the day and leave room for indoor breaks when rain arrives.

Pack for cool evenings, not beach weather

Daytime temperatures can feel manageable for walking, but evenings need a different approach. The average night low is 7.5°C, and the coldest 10% of nights fall to 3.4°C or below, so bring warm layers beneath a waterproof coat. The warmest 10% of days reach 16°C or more, offering scope for a milder afternoon without making summer clothing a sensible default. The sea averages 14.1°C and is firmly cold, so this is not a month to choose for comfortable swimming. Porto makes more sense now for travellers happy to dress for the weather than for anyone wanting to spend long stretches sitting outside.