Month guide · Seia, Portugal
Seia in December: weather and what to expect
In December, Seia averages highs of 12°C and lows of 4°C, with about 12 rainy days and 126 mm of rain. Highs are 2°C cooler than in November and 1°C warmer than in January. Crowds in Centro are low.
Is December a good time to visit?
Good for
No verdicts for Seia in December yet. They only use climate values that are precise enough to judge with.
Not ideal for
- Reliable dry weatherAbout 12 rainy days in the month
- Warm-weather holidaysHighs of only 12°C
Daily highs through December
Town-level · ERA5-Land 1991-2020Highs fall about 1°C over the month.
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 Seia |
|---|---|---|---|
| São Marcos da Serra, Algarve | 16°C | 9 | 344 km |
| Mértola, Alentejo | 16°C | 7 | 308 km |
| Odemira, Alentejo | 16°C | 9 | 323 km |
| São Bartolomeu de Messines, Algarve | 16°C | 8 | 355 km |
| Vila Nova de Milfontes, Alentejo | 16°C | 10 | 313 km |
The nearest towns with a warmer December. Distances are in a straight line.
How December is changing
Town-level · ERA5-LandDecember highs are 0.9°C warmer than in 1991-2000, and December rainfall is down about 20% (2016-2025 against 1991-2000).
Questions about Seia in December
Is December a good time to visit Seia?
It is less suited to reliable dry weather (about 12 rainy days in the month); warm-weather holidays (highs of only 12°C).
How warm is Seia in December?
Average highs are 12°C and lows 4°C. November averages 14°C and January 11°C.
Does it rain much in Seia in December?
About 12 days have at least 1 mm of rain, with 126 mm in total over the month.
Is Seia busy in December?
In December 2025, nights booked through online platforms in Centro were about 35% 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 Seia in December?
About 9 h 19 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