#1 in December
19.9°C
NOAA Season Curve (May–Oct):
M
19.3°
J
20.9°
J
22.2°
A
23.4°
S
23.7°
O
22.8°
N
21.4°
NOAA SATELLITE DATA (1991–2020 30-YEAR CLIMATOLOGY)
PTPortugal Sea Temperature in December
Historical 30-year sea surface temperatures across 44 coastlines in Portugal for December. Derived from NOAA 0.25° blended satellite and in-situ marine observations.
Climatology Notice: Temperatures represent the 30-year long-term historical average (1991–2020 normal), not a live single-day sensor forecast.
16.8°C
Bracing / Crispaverage across 44 surveyed coastlines in Portugal, December
- Ranges 14.3°C at Praia de Miramar to 19.9°C at Machico Beach.
- None of Portugal’s 44 surveyed coastlines reach the 21°C swim threshold in December.
- No month averages 21°C across Portugal as a whole, though 16 of 44 coastlines clear it in July.
- 3.9°C cooler than Portugal’s August peak of 20.7°C (see August).
Select Month
View 12-Month Annual Overview →Canary Current, Coastal Upwelling & The Nazaré Canyon
Despite sitting at Mediterranean latitudes, Portugal’s Atlantic coast and Algarve exhibit cool sea surface temperatures (averaging 18.5–20.3°C in August). Persistent northerly summer winds (the Nortada) push surface waters offshore, driving active coastal upwelling that draws deep, nutrient-rich ocean layers (14–16°C) to the shoreline. Off central Portugal at Nazaré, the continental shelf is bisected by the Nazaré Submarine Canyon (Canhão da Nazaré), a 230km long, 5,000m deep underwater chasm terminating just 1km offshore. In winter, this bathymetric trench acts as a hydraulic funnel, refracting and focusing North Atlantic storm swells into world-record 20–30m breaking waves at Praia do Norte.
Oceanographic Phenomenon:Summer Upwelling (Nortada) & Deep Canyon Wave Refraction
Thermal Lag Characteristic:Pronounced oceanic thermal lag: Atlantic water temperature peaks in late August and September (20.3°C), warming far slower than Mediterranean basins but buffering autumn cooling.
Peak Bathing Average:August / September
Portugal Beaches in December
Individual coordinate lookups from NOAA 0.25° marine grid.
Showing 44 coastlines
Explore Sea Temperatures by Country
Spain(23.6°C)Italy(25.9°C)Turkey(27.3°C)France(22.4°C)Greece(25.4°C)Cyprus(27.7°C)Croatia(25.2°C)Albania(25.5°C)Montenegro(25.7°C)Malta(26.7°C)Bulgaria(25.1°C)Romania(24.7°C)Slovenia(25.4°C)Portugal(20.7°C)Poland(19°C)Sweden(18.3°C)Netherlands(18.5°C)Bosnia & Herzegovina(25.2°C)Monaco(24.6°C)Latvia(18.5°C)Estonia(18°C)Lithuania(18.8°C)Germany(18.6°C)Denmark(18°C)Norway(15.3°C)Belgium(18.7°C)Faroe Islands(10.9°C)United Kingdom(16.1°C)Ireland(15.9°C)Iceland(10.9°C)Finland(16.6°C)
