Lagos in December: Weather, Sea Temperature and What’s Open

LAGOS · PORTUGAL · DECEMBER

December in Lagos averages 62.6°F (17.0°C) by day and 49.8°F (9.9°C) at night, with 2.96 inches of rain falling across eight days. The sea off the cliffs holds 63.2°F. On December 15 the sun is up for 9 hours 41 minutes, from 7:40 am to 5:21 pm. Five numbers, and they decide almost everything about the shape of the trip.

What the month gives you is a walking and museum coast: boardwalks above the sea in a jacket, opening hours you can actually fill, a rental car that goes where you point it. What it takes away is the swimming, the full beach day, and the evening. Last light lands before six, and the rest of the Algarve runs on the same clock.

On this page

• Average highs, lows and rain daysLagos weather in December
• Sea temperature in December63.2°F, and what that means in the water
• Crowds and prices in DecemberWhat we can date, and what we could not verify
• What’s open in Lagos in DecemberMuseum hours, closures and the Roman baths at Praia da Luz
• A two-day plan built on short daylightTwo days between 7:40 am and 5:21 pm
• December, November or January?How the three months compare
• Is December a good time to go?The verdict on December

Every figure here for air temperature and rain comes from IPMA, the Portuguese institute for the sea and the atmosphere, station 533 at Sagres, a thermometer 22.9 m above sea level, normals for 1991 to 2020. It is the nearest published station to Lagos and it stands on the windiest point of the Algarve, so read it as a coastal figure. On high ground inland the air runs colder and a good deal wetter. Sea temperature comes from somewhere else entirely, the Open-Meteo Marine API, averaged over 2015 to 2024.

Lagos weather in December: average highs, lows and rain days

IPMA’s 1991 to 2020 normals put the December average high at 62.6°F and the average low at 49.8°F, with 2.96 inches of precipitation over the month. Those readings come off a real instrument at Sagres rather than out of a reanalysis grid cell, and the difference is not cosmetic: a model square averages land, sea and hillside together, while a station tells you what one exposed clifftop did for thirty years. Lagos sits along the same coast, sheltered a little better from the westerly wind.

Eight days in an average December record at least 0.04 inch (1 mm) of rain, and 2.6 of those days record 0.39 inch (10 mm) or more. Measurable rain therefore lands roughly one day in four, and a real soaking about one day in twelve. Because a third of the wet days carry the heavy totals, the 2.96 inches arrive in bursts rather than as steady drizzle. American forecast tables usually count rain days at 0.10 inch, so these counts are not interchangeable with the ones you may be comparing them against.

Day and night sit 12.8 degrees apart, 62.6°F down to 49.8°F, which is a smaller swing than most American winters and a bigger one than a T-shirt forgives after dark. A windproof shell matters more than a thick coat on a coast IPMA describes as the windiest corner of the Algarve. Long pants for the evening, one warm layer, and the swimsuit packed on principle rather than expectation. Our packing guide has the full Portugal list.

On December 15 the sun rises at 7:40 am and sets at 5:21 pm, Portugal keeping UTC through the winter, which leaves 9 hours 41 minutes of usable light. That is the real constraint on the day. A cliff walk started in the early afternoon finishes in daylight; one started after a long lunch does not. Restaurants and museums are unbothered by this, roads and boardwalks are not.

Can you swim in Lagos in December? Sea temperature and what it feels like

The sea surface off Lagos averages 63.2°F (17.3°C) in December, from the Open-Meteo Marine API over 2015 to 2024. One caveat travels with that number: it is the mean of DAILY MAXIMA, the warmest point of each day, so it runs a shade above a true 24-hour average. Whatever a hotel chalkboard says, the water you step into at nine in the morning is cooler than 63.2°F.

In practice that is cold-water swimming, not beach swimming. Sixty-three degrees is wetsuit territory for anything longer than a few minutes, and a bracing plunge-and-out for anyone who does this at home in November. Surf schools and bodyboarders keep working the beaches through the winter in rubber. Families planning an hour in the shallows with children should read the figure as a no and spend the afternoon on the cliffs instead.

Wind and swell are the part we cannot put a number on. We found no published wave-height or wind-speed series for Lagos in December that we were willing to quote, so no figure appears for either. What we do know is where the thermometer lives: IPMA’s station sits at Sagres, the windiest point of the Algarve, and Lagos lies east of it in partial shelter.

How busy is Lagos in December? Crowds, prices and Christmas week

December sits outside the Algarve’s summer season, which is a fact of the calendar rather than of any series we hold. We found no occupancy data and no monthly room-rate data for Lagos, so we crown no month cheapest and none busiest. Two things in the month are fixed and datable instead: the Christmas and New Year week, and the museum closures on 1, 24 and 25 December.

Without rate data we will not tell you how many weeks ahead to book, because we would be inventing the number. Two bookings are worth making early on calendar grounds alone: a flight from the US across the holiday week, when everyone’s leave falls on the same dates, and a rental car if Praia da Luz or Sagres are on your list. Three nights in town covers Lagos and one day trip, four if you want the western cape as well.

We could not verify a tourist tax rate for Lagos, so we give no percentage and no per-night figure. Ask at check-in, or budget it as an unknown line alongside the rest of what a Portugal trip costs.

If you spend more on one thing this month, spend it on the car. The Museu de Lagos runs seven separate sites and one of them, a Roman bath house, sits out at Praia da Luz west of town. With 9 hours 41 minutes of daylight, a December day has room for two of those sites and a walk, not five, and the car is what decides which two.

Things to do in Lagos in December: the Mercado de Escravos and the Roman baths at Praia da Luz

December promotes the indoor half of Lagos from rainy-day fallback to main event, and the hours suddenly fit. The Rota da Escravatura opens Tuesday to Sunday, 10:00 to 13:00 and 14:00 to 18:00, with last admission half an hour before closing. In June that afternoon block competes with the beach. In December it runs from lunch until an hour after the sun has gone.

The Rota, also called the Mercado de Escravos, stands on Praça do Infante and tells Lagos’s part in the fifteenth-century slave trade. Its hardest exhibit came out of the ground in 2009, when a dig at Vale da Gafaria ahead of an underground car park opened a modern-era refuse tip holding more than 150 human skeletons: African people brought to Lagos as merchandise and, sick or dying, discarded with the town’s waste. Six other museum sites carry the rest of the story, from the Dr. José Formosinho collection to the Armazém do Espingardeiro.

Opening hours do not shift with the season, and one closure has nothing to do with December either: the museum’s own page, updated July 16, 2026, lists Forte Ponta da Bandeira as temporarily closed. Built between 1680 and 1690 to defend the quay, it has a moat and a drawbridge, and its cylindrical sentry boxes were added by restoration work around 1960. What December does change is the air around all of it, 62.6°F on the boardwalks against 63.2°F in the water, on an afternoon that ends at 5:21 pm.

We could not read a published admission price for any of the seven museum sites, so we quote no ticket cost and name no free day. The outdoor half costs nothing in any month: Praça do Infante, the town walls, the seafront, and the cliff path south toward Ponta da Piedade, which in December you walk in a fleece rather than at dawn to beat the heat.

Lagos in December: a two-day itinerary

Day one stays in town. Breakfast after the 7:40 am sunrise, then Praça do Infante for the 10:00 opening of the Rota da Escravatura, which gives you three hours before it shuts at 13:00. Eat while it is closed. Take the cliff path south at about 14:30, turn around with an hour of light in hand, and be back in the streets before 5:21 pm, when the day ends whether or not you are finished.

Day two goes west by car: Praia da Luz for the Roman bath house, then the cape at Sagres where the IPMA thermometer stands, and back for dinner in the dark. If one of the month’s eight wet days lands on you, or one of the 2.6 heavy ones, flip the order and hold the 14:00 to 18:00 museum block as your shelter. Avoid Mondays, when the Rota is closed, and 24 and 25 December, when every site is.

Lagos in December vs November and January

December’s 62.6°F high runs 3.6 degrees below November and 1.6 degrees above January, and the nights follow the same slope, 53.1°F to 49.8°F to 47.3°F. Rain falls away steadily across the three: 3.23 inches over 8.4 days, then 2.96 over 8.0, then 2.10 over 7.4, making January the driest of the trio by a clear margin. The sea cools the whole way down, 64.4°F to 63.2°F to 61.4°F, all three from the marine API rather than the IPMA station.

Shift four weeks earlier and November hands you 3.6 degrees more daytime warmth, 1.2 degrees more water and longer afternoons, in exchange for 0.27 inch more rain and an extra half day of it. Shift four weeks later and January gives the driest month on the list, at the cost of 1.8 degrees of sea and the coldest nights of the three. December is the middle term on every line except rain, where it already leans toward January.

Is December a good time to visit Lagos?

Yes if you came to walk, look and drive. Cliff paths at 62.6°F, seven museum sites with published hours, a coast road without summer traffic, and a town you can cross on foot between two meals. No if the trip is built on water or on daylight: 63.2°F of sea and 9 hours 41 minutes of it are not enough for a beach vacation, and no amount of good luck with the eight wet days will change that.

If the answer is no, the fix depends on what you wanted. Anyone chasing warmth should slide back to November, 66.2°F by day and 64.4°F in the sea, and accept 3.23 inches of rain. Anyone chasing dry weather should slide forward to January, 2.10 inches over 7.4 days, the lightest rainfall of the three, with colder nights at 47.3°F. Swimmers should stop looking at winter altogether and read the twelve-month view.

One oddity belongs to December: the sea reads warmer than the afternoon air, 63.2°F against a 62.6°F average high, so the coldest thing on the cliff path is the wind, not the water below it.

The last word

Book Lagos in December for the walking and the reading, not the swimming, and give yourself the car that reaches Praia da Luz before the light goes. One detail the museum publishes plainly, and one reason to check its page again before you build a morning around the fort: inside those very thick seaward walls, laid out to cross fire with the Porta da Vila and the Castelo dos Governadores, sits a small seventeenth-century chapel lined with azulejos, shut along with everything else behind the drawbridge.

Sources & data for this guide

• December air normals, 62.6°F / 49.8°F / 2.96 in · IPMA, climatological normals 1991-2020, station 533 Sagres, 22.9 m · checked Sep 23, 2026
• Rain-day counts at the 1 mm and 10 mm thresholds (8.0 and 2.6 days) · IPMA 1991-2020, station 533 Sagres · checked Sep 23, 2026
• November and January normals and rain days · IPMA 1991-2020, station 533 Sagres · checked Sep 23, 2026
• Sea surface 63.2°F, and 64.4°F / 61.4°F for the neighboring months, as means of daily maxima · Open-Meteo Marine API, 2015-2024 · checked Sep 23, 2026
• Daylight of 9 h 41 min, sunrise 7:40 and sunset 17:21 UTC on December 15 · sunrise-sunset.org · checked Sep 23, 2026
• Museum hours, closure dates, the temporary closure of Forte Ponta da Bandeira, the 1680-1690 construction and the 2009 Vale da Gafaria excavation · Museu de Lagos, Câmara Municipal de Lagos, page updated July 16, 2026 · checked Sep 23, 2026
• We could not read a published admission price for any Museu de Lagos site, nor any occupancy or room-rate series for Lagos, nor a tourist tax rate, so we give no ticket price, no crowd ranking and no tax percentage.

To plan your stay

• Best Time to Visit Lagos: Weather, Sea Temperature and the Quiet Months
• Lagos in January: Weather, Sea Temperature and Which Museum Sites Open
• Lagos in November: Weather, Sea Temperature and What's Open
• Lagos in February: Weather, Sea Temperature and What Is Closed

Nearby places

• Ponta da Piedade: Cliff Walkways, Grotto Boats and the Best Time of Day
• Sagres, Portugal: Wind, the Beaches on Both Sides and Cabo de São Vicente
• Albufeira, Portugal: The Three Zones, the Beaches and the Old Town Hill