Cascais weather in December
Temperature, sea and sunshine in December: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in December
Poor
Best time to visit: June – September
What is the weather like in Cascais in December?
In December, Cascais is cool: daytime highs average 15 °C, and nights cool down to about 11 °C. The sea averages 16.1 °C – swimming is only for the hardy. Expect around 5 hours of sunshine a day. Rain is frequent, with about 10 rainy days and 83 mm in total. All in all, December is not an ideal month for a holiday in Cascais.
December compared
How the weather changes from November to January. Tap a month to open it.
| NovemberNov | DecemberDec | JanuaryJan | |
|---|---|---|---|
| Score | 19 | 18 | 19 |
| Day | 17° | 15° | 15° |
| Night | 13° | 11° | 10° |
| Sea | 17° | 16° | 15° |
| Sun | 5 h | 5 h | 5 h |
| Rain days | 10 | 10 | 9 |
More details for December
- Daylight
- 9 h 29 min07:48 – 17:17
- UV index
- 2 · lowclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or more
- Wind
- 23 km/haverage daily peak
- Cloud cover
- 55 %on average
- Hot days
- 0 days30 °C or more
- Time zone
- UTC+0Europe/Lisbon
How the score comes together
- Temperatureweight 35 %0 %
- Seaweight 25 %0 %
- Sunshineweight 20 %30 %
- Few rainy daysweight 20 %61 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in December
- A jumper for the evenings
- Rain jacket or umbrella
Cascais in December: quick answers
Is Cascais hot in December?
No. In December, Cascais is cool: daytime highs average 15 °C and nights drop to about 11 °C.
Can you swim in Cascais in December?
Only if you don't mind cold water: in December the sea averages just 16.1 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Cascais in December?
Rain is frequent, with about 10 rainy days and 83 mm in total.
Cascais month by month
The whole year in CascaisAll destinations: PortugalWhere to go in DecemberSea temperature in December
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0)