Month guide · Sines, Portugal
Sines in December: weather and what to expect
The sea is still cool, around 16°C. In December, Sines averages highs of 16°C and lows of 10°C, with about 10 rainy days and 81 mm of rain. Highs are 2°C cooler than in November and 1°C warmer than in January. Crowds in the Alentejo are low.
Is December a good time to visit?
Good for
No verdicts for Sines in December yet. They only use climate values that are precise enough to judge with.
Not ideal for
- Reliable dry weatherAbout 10 rainy days in the month
Daily highs through December
Town-level · ERA5-Land 1991-2020Highs fall about 1°C over the month. A day above 20°C happens in roughly 1 December in 6; nights below 5°C in about 1 in 3.
December in detail
Town-level · ERA5-LandCrowds, holidays and daylight
Public holidays in December 2026
- 1 Dec Restoration of Independence Day
- 8 Dec Immaculate Conception
- 25 Dec Christmas Day
Local (municipal) holidays are not included.
Warmer in December
Where is warm in December →| Place | High | Rain days | From Sines |
|---|---|---|---|
| Aljezur, Algarve | 16°C | 10 | 71 km |
| Bensafrim, Algarve | 16°C | 9 | 90 km |
| São Marcos da Serra, Algarve | 16°C | 9 | 79 km |
| Odemira, Alentejo | 16°C | 9 | 45 km |
| Vila Nova de Milfontes, Alentejo | 16°C | 10 | 27 km |
The nearest towns with a warmer December. Distances are in a straight line.
How December is changing
Town-level · ERA5-LandDecember highs are 0.7°C warmer than in 1991-2000, and December rainfall is down about 35% (2016-2025 against 1991-2000). Days above 20°C in December went from 0.1 to 0.6 a year on average.
Questions about Sines in December
Is December a good time to visit Sines?
It is less suited to reliable dry weather (about 10 rainy days in the month).
How warm is Sines in December?
Average highs are 16°C and lows 10°C. November averages 18°C and January 15°C.
Does it rain much in Sines in December?
About 10 days have at least 1 mm of rain, with 81 mm in total over the month.
Is Sines busy in December?
In December 2025, nights booked through online platforms in the Alentejo were about 15% of the busiest month, which we count as low. The figure is for the whole region and leaves out hotels.
How long are the days in Sines in December?
About 9 h 33 min from sunrise to sunset in the middle of the month.
Sources
Climate: ERA5-Land, Copernicus Climate Change Service (C3S) Climate Data Store, contains modified Copernicus information (CC BY 4.0). Crowds: Eurostat, nights spent in short-stay accommodation booked through online platforms (tour_ce_omn12) (CC BY 4.0). Place names and populations: GeoNames (CC BY 4.0). Climate averages cover 1991-2020. Daylight: calculated from the town's coordinates. Full methodology